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Natural inorganic gem materials · Mineral species · Natural identity; treatment status unknown

Fluorite

Also known asBlue Fluorite · Blue John

A mineral species with formula CaF2, adopted as a basic name in GB/T 16552-2017 Table A.2; it is relatively soft with distinct cleavage, so a caution is needed for everyday wear such as in bracelets. This page compares how the major standards and institutions name it, what must be disclosed when selling it, whether it can be worn every day, how it is treated and identified, and which source each conclusion comes from.

Price, rarity and origin are outside the scope of this wiki.

Edited by RalphReviewed by JuneLast updated 2026-10-12Who maintains this page

FAQCare and wear

Questions people ask about Fluorite

Every sentence below is followed by the registered fact it rests on; answers add no new facts and promise no outcome.

Q1What colours does fluorite come in, and does it glow under UV?

Fluorite comes in green, purple, violet, blue, yellow, orange, pink and brown, and can also be colourless.CIBJO Gemmological Laboratories Book 2024Its colour is commonly zoned.Handbook of MineralogyYes: fluorite commonly fluoresces blue, violet, green, yellow or red under UV, and may also be phosphorescent, thermoluminescent or triboluminescent.Handbook of MineralogyA colour-change effect is also recorded in fluorite.GB/T 16553—2017

Q2Is there synthetic fluorite, and what are real fluorite's telltale traits?

No synthetic fluorite is commercially available.CIBJO Gemstone Book 2022Its crystals are usually cubes, octahedra, rhombic dodecahedra or combinations of these, and granular or massive aggregates also occur.GB/T 16553—2017It has perfect cleavage in four directions.GB/T 16553—2017Its Mohs hardness is 4.GB/T 16553—2017Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.What this page can answer

Q3Is fluorite too soft and fragile for jewellery?

It needs care: fluorite has low hardness, so it scratches easily, and it cleaves or fractures easily or is brittle, so it should be worn with care.CIBJO Gemstone Book 2022Its cleavage is perfect and its tenacity brittle.Handbook of MineralogyProng settings call for extreme caution, and bezel, flush, channel and pavé are best avoided, because it has four perfect cleavages.Gems & Gemology 1987 (Martin)

Q4How and where does fluorite form?

Fluorine-bearing fluids become enriched during magmatic differentiation or within hydrothermal systems.Handbook of MineralogyUnder low- to high-temperature conditions, calcium and fluorine combine to precipitate cubic fluorite, commonly alongside other gangue and sulfide minerals.Handbook of MineralogyFluorite of economic value comes chiefly from stratabound deposits and from hydrothermal veins of low to high temperature, and it can also cement sandstones.Handbook of MineralogyIt also occurs as an accessory mineral in granite, granite pegmatites and syenites, around fumaroles, and in carbonatites and alkaline intrusives.Handbook of Mineralogy

Q5Is fluorite heated, irradiated or filled?

Yes: black and dark blue fluorite is commonly heated to blue, and the result is stable and hard to detect.GB/T 16553—2017Colourless fluorite can be turned purple by irradiation, but that colour fades easily in light and is very unstable; irradiation can also give fluorite phosphorescence it did not have.GB/T 16553—2017Filled fluorite shows a different lustre and gas bubbles in the filled part under magnification, and filler containing a fluorescent agent makes the fissures fluoresce and phosphoresce strongly under UV.GB/T 16553—2017

Q6How should you clean fluorite, and what should it avoid?

Ultrasonic and steam cleaners should be avoided, and so should heat.Gems & Gemology 1987 (Martin)It fuses under a jeweller's torch, and sulfuric acid decomposes it.Gems & Gemology 1987 (Martin)

Q7Does fluorite lose its colour in sunlight?

Sunlight and artificial light are rated relatively safe for fluorite, while heat in a display case calls for caution.Gems & Gemology 1987 (Martin)The exception is purple produced by irradiating colourless fluorite, which fades easily in light.GB/T 16553—2017

Q8Is fluorite toxic?

For sodium fluoride and other inorganic solid fluorides, the NIOSH Pocket Guide to Chemical Hazards gives a workplace exposure limit of 2.5 milligrams per cubic metre (as fluorine) as a time-weighted average; the guide does not name fluorite or say anything about wearing finished jewellery.NIOSH Pocket Guide: sodium fluorideNaming, disclosure and labelling information on this site is reference material and does not constitute legal advice. Actual labelling duties follow the regulations in force in each jurisdiction and the testing certificates that accompany the goods; verify independently or consult a professional before relying on it.What this page can answer

Q9What has fluorite been used for, and does it have healing powers?

There is no scientific evidence that fluorite has healing powers: the UK advertising regulators ASA and CAP state that they have not seen evidence that crystal therapy can treat medical conditions.ASA/CAP guidance (UK)Museum collections show fluorite used for scholar's-table and display objects in the 18th–19th centuries, such as English Blue John candelabra and columns, with only one bead necklace.The Met 02.18.905 · The Met 02.18.906 +4Its name comes from the Latin word for to flow, in allusion to its low melting point.Handbook of Mineralogy

What this page can answer

This page covers

What we cannot conclude

  • Whether one particular bead is natural, treated or synthetic — only a laboratory report can settle that.
  • Geographic origin, unless an origin report accompanies the item.
  • Price, rarity or investment value: this wiki covers naming and disclosure only.

Material research: formation, causes and history

What authoritative sources say about how this material forms, what causes its colour and optical effects, where its name comes from and how people have used it. Each statement carries an evidence grade and its sources; it describes the material in general, not any specific piece.

How it forms

Fluorite (CaF2) is calcium fluoride, crystallizing in the cubic system and found chiefly both as an accessory mineral and as a vein mineral of hydrothermal origin. Accessory fluorite appears in granites, granite pegmatites and syenites, around fumaroles, and in carbonatites and alkaline intrusives, while deposits of economic value are worked from stratabound bodies and from hydrothermal veins that range across low to high temperatures; the mineral may also form a cement in sandstones. Quartz, dolomite, calcite, barite, celestine, sulfides, cassiterite, topaz, wolframite, scheelite and apatite are its frequent companions, consistent with deposition from migrating fluorine-rich fluids.

Scope: Covers the origin and occurrence of fluorite as a hydrothermal-vein/accessory mineral; does not include deposit-specific geochronology or quantitative genetic model details.

Sources Handbook of Mineralogy

Where it forms

Accessory mineral of granites, granite pegmatites and syenites; also around fumaroles and within carbonatites and alkaline intrusives.

Sources Handbook of Mineralogy

Veins of hydrothermal origin spanning low-to-high temperatures, together with stratabound deposits; it also serves as sandstone cement.

Sources Handbook of Mineralogy

How it forms, step by step

  1. Fluorine-bearing fluids are enriched during magmatic differentiation or within hydrothermal systems.

    Sources Handbook of Mineralogy

  2. The fluorine-rich fluids migrate along fractures, faults, or bedding spaces.

    Sources Handbook of Mineralogy

  3. Under low- to high-temperature conditions, calcium and fluorine combine to precipitate cubic fluorite, commonly intergrown with other gangue and sulfide minerals.

    Sources Handbook of Mineralogy

  4. It may crystallize as an accessory phase in igneous rocks, form around fumaroles and in carbonatites and alkaline rocks, and can cement sandstones.

    Sources Handbook of Mineralogy

Link to appearance

Fluorite occurs in many colors (colorless, white, purple, blue, green, yellow, orange, red, etc.), commonly zoned, with vitreous luster; it often fluoresces blue, violet, green, yellow, or red under UV and may also be phosphorescent, thermoluminescent, or triboluminescent.

Sources Handbook of Mineralogy

Timescale

The source does not state an absolute geological timescale for fluorite formation.

Sources Handbook of Mineralogy

Supporting findings

Fluorite occurs as an accessory mineral in granite, granite pegmatites, and syenites, and around fumaroles and in carbonatites and alkaline intrusives.

Evidence grade B

Scope: A general occurrence summary, not a quantitative deposit model.

Sources Handbook of Mineralogy

Fluorite of economic value is recovered chiefly from stratabound deposits and from hydrothermal veins that span low to high temperatures; it may additionally serve as a cement within sandstones.

Evidence grade B

Scope: Describes deposit types and modes of occurrence, not specific P-T or ages.

Sources Handbook of Mineralogy

Recorded localities

Authoritative sources list the localities below; the list is not exhaustive.

Locality sketch mapLand outlines only; the map does not depict any national or regional boundary. Dots mark approximate positions. Base map: Natural Earth (public domain).

Asia

Europe

Seas and coasts

These are localities recorded by authoritative sources, not an origin finding for any individual piece. The CIBJO Gemstone Book (2022, §4.2.3) says a place of origin names where a gem was mined or harvested, is a matter of opinion, does not imply a level of quality, and that cutting, processing or exporting centres must not be used to imply origin. See how far testing can go on this page, the origin determination guide and the overview of recorded localities.

Causes of colour and optical effects

Fluorite commonly fluoresces blue, violet, green, yellow, or red under UV and may also be phosphorescent, thermoluminescent, or triboluminescent.

Evidence grade B

Scope: The source records the fluorescence phenomena but gives no specific activator or causal explanation.

Sources Handbook of Mineralogy

Human use and museum objects

Collection evidence shows fluorite used for scholar's-table and display objects in the 18th-19th centuries (e.g. Met 02.18.905 ink stand, 55.148.1a-h candelabra, 2019.283.48a, b Blue John columns), with beadwork limited to a single 19th-20th century necklace (Met 48.187.574); object use predominates in the collection.

Evidence grade A

Scope: Applies to collection objects recorded as fluorite/fluorspar or Derbyshire spar; modern fluorite specimens are not covered.

Sources The Met 02.18.905 · The Met 02.18.906 · The Met 2019.283.48a, b +3

Fluorite (including English Derbyshire 'Blue John') appears in the collection chiefly as objects rather than beadwork. Qing-dynasty China (18th century) produced two fluorite carvings - an ink stand (Met 02.18.905) and a figure (Met 02.18.906); 18th-century England worked Blue John fluorspar into candelabra and ornamental columns (Met 55.148.1a-h, 2019.283.48a, b); and a 1906 Easter Egg (Met 51.91.1) is set with fluorite. Only one 19th-20th century fluorite necklace is beadwork (Met 48.187.574). Its use is therefore mainly scholar's-table, display and decorative ware rather than beadwork.

Sources The Met 02.18.905 · The Met 02.18.906 · The Met 2019.283.48a, b +3

Scope: A museum object evidences only the existence and date of that artefact itself; it does not establish widespread ancient use of the material, nor does it attest the origin, naturalness, or treatment of any modern specimen.

Objects cited

1700175018001850190019502000Met 02.18.90518th centuryMet 02.18.90618th centuryMet 2019.283.48a, b18th centuryMet 55.148.1a–hsecond half 18th centuryMet 48.187.57419th–20th centuryMet 51.91.11906
Dates of museum objectsDates from the museums' open-access records (CC0); each bar spans the whole period named in the record, with qualifiers such as “early” or “possibly” kept in the label rather than turned into a narrower range; an arrow marks a record that reads “before” or “after” a yearSource: The Met / Cleveland Museum of Art open-access records

Other research findings

Fluorite is calcium fluoride (CaF2), cubic, space group Fm3m, with a = 5.4626 and four formula units per unit cell (Z).

Evidence grade B

Scope: Refers to the ideal composition; density increases when rich in rare-earth elements.

Sources Handbook of Mineralogy

The name fluorite is derived from the Latin word 'to flow', in allusion to its low melting point.

Evidence grade B

Scope: Name etymology only; unrelated to formation.

Sources Handbook of Mineralogy

The NIOSH Pocket Guide to Chemical Hazards sets a recommended exposure limit, and lists the OSHA permissible exposure limit, of 2.5 milligrams per cubic metre as a time-weighted average for sodium fluoride (as fluorine), and notes that both limits also apply to other inorganic, solid fluorides (as fluorine).

Evidence grade A

Scope: Summarises a US occupational exposure limit for airborne dust in the workplace; the cited text does not name this mineral and says nothing about wearing or handling finished jewellery. Not medical advice. Not legal advice.

Sources NIOSH Pocket Guide: sodium fluoride

Limits of this research

  • Research status: Formation, occurrence or other material-specific findings found in authoritative sources
  • The source is a mineral data sheet focused on properties and occurrence; it gives no absolute ages for fluorite formation.
  • Fluorescence is recorded, but its activator/mechanism is not explained in this source.

Methodology

Evidence grades

A
Standards bodies, government geological surveys, peer-reviewed research and museum records
B
Institutional educational material
C
Specialist databases or cautious readings

A statement is never graded above its strongest source.

This section is LumaLark's own factual restatement of public authoritative sources, credited item by item; it contains no verbatim excerpts, images or third-party logos.

DecideListing name, disclosure, care and treatments

Suggested listing name
Fluorite

GB/T 16552—2017 Table A.2 “Fluorite” · CIBJO Gemmological Laboratories Book 2024 §7.2.1.90 “Fluorite”

Construction or treatment status

Natural identity; treatment status unknown

Treatments recorded for this material: Heated / Heat-treated, Filled / Fracture-filled, Coated, Irradiated

Related:Disclosure and cautions

This page cannot answer

Natural? · Origin · Price

A lab report settles these; this wiki covers naming and disclosure.

Related:What this page can answer

Answer at a glance

Fluorite is Fluorite (CaF2); use "Fluorite" for listings, and disclose any known treatments.

What this means for you

Before buying, check the recommended listing name "Fluorite" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.

Known uncertainty

Last reviewed
2026-09-01

Care and wear

Normal care for every gemstone (CIBJO Gemstone Book §6.1), in brief:

  • Handle it gently.
  • Store pieces apart when not worn, so they cannot scratch each other.
  • Clean with warm soapy water and a soft brush.
  • Use ultrasonic cleaners only with caution.

The §6.1 wording and the full list of §6.2 special-care letters cited on this page are on the general gem care page.

Care

care (cleaning)2 sources compared

Fluorite — care (cleaning): Some stones are susceptible to damage from ultrasonic cleaning. Do not expose them to ultrasonic cleaning.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code j

Treatment state
any treatment state
Source & check 2026-09-25
Source
Fact checked on
2026-09-25

Fluorite — care (cleaning): ultrasonic and steamer: avoid; note: avoid heat.

Gems & Gemology 1987 (Martin)

Treatment state
untreated
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Fluorite — care (cleaning): Some stones are susceptible to damage from ultrasonic cleaning. Do not expose them to ultrasonic cleaning.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code j

Treatment state
any treatment state
Applies only to
Blue John
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Fluorite — care (chemicals): Treatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code k

Treatment state
treated
Only after these treatments
impregnation
Applies only to
Blue John
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Fluorite — care (wear): low hardness, so it scratches easily; wear with care; cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code a, special-care code b

Treatment state
any treatment state
Source & check 2026-09-25
Source
Fact checked on
2026-09-25

Fluorite — care (wear): low hardness, so it scratches easily; wear with care; cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code a, special-care code b

Treatment state
untreated
Applies only to
Blue John
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Fluorite — care (setting): prong: use extreme caution; bezel, flush, channel and pavé: avoid; note: four perfect cleavages.

Gems & Gemology 1987 (Martin)

Treatment state
untreated
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Fluorite — care (repair): jeweller's torch, pickle pot, polishing and thermal shock: avoid; note: avoid heat, as it fuses under the torch; sulfuric acid decomposes it.

Gems & Gemology 1987 (Martin)

Treatment state
untreated
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Fluorite — care (display): sunlight and artificial light: relatively safe; heat in the display case: use caution; note: avoid heat.

Gems & Gemology 1987 (Martin)

Treatment state
untreated
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Each row's “Source & check” expands to the full source; the date beside it is the fact check date.

Common care questions and matching entries

CleaningCare for Fluorite: CIBJO states that it must not be cleaned ultrasonically, in any treatment state, and the entry limited to Blue John fluorite likewise states that it must not be cleaned ultrasonically, in any treatment state. Martin, Gem DurabilityMartin, Gemstone Durability: Design to Display, states for untreated Fluorite: ultrasonic and steam cleaning should be avoided; in repair, the jeweller's torch, pickle pot, polishing and thermal shock should be avoided, heat should be avoided, it fuses under the torch, and sulfuric acid decomposes it; on display, sunlight and artificial light are relatively safe, while heat in the display case needs caution; in setting, prong setting needs extreme caution and bezel, tension, channel and pavé settings should be avoided, as it has four perfect cleavages. CIBJO also states that it has low hardness, scratches easily and breaks easily, so wear it with care; the Fluorite clause applies to any treatment state and the Blue John clause to untreated material. ChemicalsOn chemicals, CIBJO's entry limited to impregnated Blue John states that dye, oil, resin, wax or plastic treatments are not permanent, so keep it away from all solvents (including dish-washing liquids), chemicals and heat.

This table scrolls sideways on narrow screens.

QuestionMatching entries
Can it go in an ultrasonic or steam cleaner?care (cleaning); ultrasonic and steamer: avoid; note: avoid heat; Blue John: care (cleaning)
Heat and thermal shockjeweller's torch, pickle pot, polishing and thermal shock: avoid; note: avoid heat, as it fuses under the torch; sulfuric acid decomposes it
Light and displaysunlight and artificial light: relatively safe; heat in the display case: use caution; note: avoid heat
Contact with acids, alkalis and household chemicalsBlue John: Treatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat
Wearing limits (knocks, settings)low hardness, so it scratches easily; wear with care; cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care; Blue John: low hardness, so it scratches easily; wear with care; cleaves or fractures easily or is brittle (e.g. rubbed facet edges); wear with care; prong: use extreme caution; bezel, flush, channel and pavé: avoid; note: four perfect cleavages

Care entries by treatment state

The same entries grouped by the treatment state each applies to; each links to its full wording and source. Letters are CIBJO special-care codes, explained on the gemstone care page.

any treatment state

untreated

treated (Only after these treatments: impregnation)

Treatments and identification leads

Registered treatmentsThe treatments recorded for Fluorite are irradiation, filling, heating and coating. Irradiation has the status irradiated or dyed; filling, heating and coating have the status treated. Stability and frequencyThe cited sources give no stability or prevalence for any of them, which is recorded as a dash, not none. Irradiation can turn colourless Fluorite purple; the colour fades easily on exposure to light and is very unstable, and fluorite that had no phosphorescence may become phosphorescent. Filled areas differ in lustre from the host and contain bubbles; infrared spectroscopy can detect the filler's characteristic bands, and luminescence imaging equipment can show the filler's distribution. Heating often turns black or dark blue fluorite blue; the colour is stable and hard to detect. Coating shows anomalous lustre and local peeling of the film under a loupe, and refractive index readings may be abnormal.

This table scrolls sideways on narrow screens.

TreatmentMarket frequency (CIBJO)Stability (CIBJO)GB/T 16552 categoryJJA/AGL listingIdentification leads
irradiationStatus: irradiated or dyed——Treatmentirradiation (blue)See identification leads
fillingStatus: treated——Graded — see §5.4.1, Table 1—See identification leads
heatingStatus: treated——Optimization—See identification leads
coatingStatus: treated——Treatment—See identification leads

Where each treatment acts (schematics): Irradiated · Filled / Fracture-filled · Heated / Heat-treated · Coated

“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16553—2017; GB/T 16552—2017 Table B.1; JJA/AGL 2025

Whether a treatment has to show in the name differs between the two rule sets (this site’s paraphrase):

  • GB/T 16552—2017: a method classed as treatment has to be stated in the name itself — the method put before the name, or added in brackets after it; a method classed as optimization does not need to appear in the name, though one marked “Optimization (annotation required)” still has to be noted in the quality documents. Source: §5.4.2.1 a), b); §5.4.2.2 a)
  • CIBJO Gemstone Book 2022: no longer splits treatments into ones that need specific disclosure and ones that need only general disclosure: every treatment is to be disclosed, and the seller tells the buyer which treatment was used and what special care it calls for. Source: §4.2.5 Note 2, §4.2.5.1, pp.14–15

What this table covers

What this page can give

  • Registered treatments, their stability and how often they occur (see the table above)
  • Identification leads for each treatment, for use when sending a stone for testing

VerifyNames, standards, technical facts, clauses and sources

Names

Besides Fluorite, the name register records "Blue Fluorite" and "Blue John", for which no restriction on use as a name is recorded (CIBJO Gemstone Book 2022 Annex 8 “Blue Fluorite”; CIBJO Gemmological Laboratories Book 2024 §7.2.1.31 “Blue John”; CIBJO Gemstone Book 2022 Annex 8 “Blue John”); one further name in a non-Latin script is listed in the name register below (1 with no restriction recorded on use as a name).

Standard and listing namesThe Chinese formal name of Fluorite comes from GB/T 16552—2017 Table A.2, and the suggested listing name is also Fluorite. Trade and mineralogical namesThe mineralogical name is Fluorite (CaF2). Names in four languagesThe four-language names are the Simplified and Traditional Chinese names, English Fluorite and the Japanese names, the Japanese form also being the GSJ (Japan) formal name. Candidate search termsThe JJA/AGL Gemstone Nomenclature 2025 also records a transliterated form, as a search candidate only. National standard namesAmong national and regional formal names, Germany (RAL) uses Fluorit/Flussspat and the European Union Fluorite. Institution usageFor authority wording, the CIBJO Gemmological Laboratories Book 2024 records Fluorite; the FTC text on file has no wording for this name (checked); GIA and Gem-A are unchecked. Bodies without a recorded wording show the entry's own English name, which does not represent their position. Names such as Blue Fluorite and Blue John are also recorded.

Name register

Every name recorded for this entry, with how it is classified, whether it may be matched to this entry automatically, whether it may be used as a product name, and the clause it rests on.

This table scrolls sideways on narrow screens.

NameTypeMatchingUse as a nameBasis
no restriction recorded (3)
Blue FluoriteEnglishnarrower name (variety or subtype)matched automaticallyno restriction recordedCIBJO Gemstone Book 2022 Annex 8 “Blue Fluorite”
Blue JohnEnglishmarket namematched automaticallyno restriction recordedCIBJO Gemmological Laboratories Book 2024 §7.2.1.31 “Blue John”; CIBJO Gemstone Book 2022 Annex 8 “Blue John”
フルオライトJapanesetransliterationsearch candidate onlyno restriction recordedJJA/AGL Gemstone Nomenclature 2025 p.16

How each authority words this name: see Names › Authority wording.

Authority wording

GIA, FTC, CIBJO, Gem-A
Fluorite (on record for CIBJO (CIBJO Gemmological Laboratories Book 2024 §7.2.1.90); no wording for this name in the FTC text on file; GIA, Gem-A unchecked — bodies without a recorded wording show the entry's own English name)
GSJ (Japan) formal name
フローライト／蛍石
Chinese formal name
萤石 (GB/T 16552—2017 Table A.2)
Mineralogical name
Fluorite (CaF2)
Trade names and synonyms
Blue John (market name) · Blue Fluorite (narrower name (variety or subtype))

Four-language names

简体中文
萤石
繁體中文
螢石
English
Fluorite
日本語
フローライト／蛍石

National and regional formal names

Germany (RAL)
Fluorit / Flussspat
European Union
Fluorite

See also: Misleading and prohibited trade names · Supplementary name index

Classification

Origin
Natural materials
Material domain
Natural inorganic gem materials
Browsing family
Halide minerals
Identity tier
Mineral species
Mineral chemical class
Halides
Construction or treatment status
Natural identity; treatment status unknown

Treatments listed by standards

GB/T 16552-2017, Annex B, Table B.1

Table B.1, row “Fluorite” (p.16):

This table scrolls sideways on narrow screens.

MethodEffectCategory
HeatingImproves colourOptimization
FillingImproves or changes durability and appearanceGraded — see §5.4.1, Table 1
CoatingImproves or changes lustre, colour and other aspects of appearanceTreatment
IrradiationChanges colourTreatment

What Table B.1 is, and how the “see 5.4.1” grades are defined: see the GB/T 16552: optimization vs treatment page.

JJA/AGL (Japan) table of principal gem names, 2025

This table scrolls sideways on narrow screens.

Gem nameSpeciesColourListed in the tableNotes
[colour] FluoriteFluoritecolourless, white, violet, blue, green, yellow, orange, red, pink, brownan untreated tier is listed
[colour] FluoriteFluoritebluethe source lists no untreated tier; irradiation (Irradiated)

JJA/AGL definitions and nomenclature (2025 revision), table of principal gem names, p.16

How to read the JJA/AGL table: see the Gem treatments page.

What it is and how it's identified

Registered material facts for Fluorite: composition CaF2, the phase being fluorite; crystalline or a crystalline aggregate, cubic, with crystal habits commonly cubes, octahedra, rhombic dodecahedra and their combinations, and also granular or massive aggregates. Mohs hardness is 4, with four sets of perfect cleavage, and when untreated the tenacity is brittle. Density is 3–3.25 g/cm³, derived from the cited clause value of 3.18 with an allowed deviation of +0.07/−0.18. Optically it is isotropic, often an isotropic aggregate; the refractive index is 1.433–1.435, derived from the cited clause value of 1.434 with an allowed deviation of ±0.001; there is no birefringence. Transparency is transparent to translucent. When untreated, there is no pleochroism, the lustre is vitreous to subvitreous, and fluorescence varies with colour, is usually strong and may include phosphorescence. The UV-Vis spectrum is not diagnostic, the mid-infrared region shows the characteristic infrared absorption bands of fluorite, and a colour-change effect may be seen.

Registered material facts

Each row carries its own source and check date and can be cited on its own; “—” means the cited source gives no value, not “none”.

Definition

Fluorite — nomenclature status: IMA status G: grandfathered (described before the IMA existed, and generally regarded as a valid species).

CIBJO Gemmological Laboratories Book 2024

Source & check 2026-09-22
Source
Fact checked on
2026-09-22

Fluorite — composition (chemistry): CaF2

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — composition (phase): fluorite

CIBJO Gemmological Laboratories Book 2024

Source & check 2026-09-22
Source
Fact checked on
2026-09-22

Structure

Fluorite — structure (overall): crystalline, or else a crystalline aggregate

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — structure (crystal system): cubic

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — structure (crystal habit): Cubes, octahedra, rhombic dodecahedra and their combinations are usual; granular or massive aggregates also occur.

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Durability

Mohs hardness2 sources compared

12345678910GB/T 16553—20174Handbook of Mineralogy4References (diamond = value, bar = range; below)

Reference points on this site: Talc 1–3, Apatite 5–5.5, Orthoclase 6–6.5, Topaz 8, Diamond 10 (Source: GB/T 16553—2017); Gypsum 1.5–2, Calcite 3, Quartz 7 (Source: Handbook of Mineralogy); Corundum 9 (Source: GIA Gem Encyclopedia (care guide))

Mohs hardnessSource: GB/T 16553—2017 · Handbook of Mineralogy

Fluorite — Mohs hardness: 4

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Fluorite — Mohs hardness: 4

Handbook of Mineralogy

Source & check 2026-09-20
Source
Fact checked on
2026-09-20

Fluorite — cleavage: perfect in four directions

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — toughness: cleavage perfect; tenacity brittle

Handbook of Mineralogy

Treatment state
untreated
Source & check 2026-09-20
Source
Fact checked on
2026-09-20

Physical properties

Fluorite — density: 3–3.25 g/cm³

GB/T 16553—2017

0.51.52.53.54.55.56.57.53–3.25
Specific gravitySource: GB/T 16553—2017
Does this standard apply
applies to this entry
Qualification

The clause we cite gives 3.18, with a stated tolerance of +0.07 / -0.18. The range shown here is worked out from that.

Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Optical

Optical effects on record: colour change

Fluorite — optic character: isotropic, usually as an isotropic aggregate

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — refractive index: 1.433–1.435

GB/T 16553—2017

1.31.72.12.52.93.31.433–1.435
Refractive indexSource: GB/T 16553—2017
Does this standard apply
applies to this entry
Qualification

The clause we cite gives 1.434, with a stated tolerance of ±0.001. The range shown here is worked out from that.

Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — birefringence: none

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — transparency: transparent to translucent.

CIBJO Gemmological Laboratories Book 2024

Source & check 2026-09-22
Source
Fact checked on
2026-09-22

Fluorite — pleochroism: none

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — fluorescence (overall): varies with colour; generally strong; may be phosphorescent.

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — spectrum (UV-visible): non-characteristic

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — spectrum (infrared): Mid-IR absorption follows the pattern typical of fluorite

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — optical effect (colour change): seen

GB/T 16553—2017

Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — magnification: gas-liquid inclusions, color band, cleavage, aggregate of granular structure.

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

body colour2 sources compared

Fluorite — body colour: green, blue, brown, yellow, pink, purple, colorless, etc.

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
Qualification

In chapter 5 of GB/T 16553—2017, the colour entries of Apatite, Zoisite, Amblygonite and other variety clauses also name green or a greenish colour.

General note
colour alone is not identity
Source & check 2026-09-26
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-26)
Fact checked on
2026-09-26

Fluorite — body colour: Green, purple, violet, blue, yellow, colourless, orange, pink, brown.

CIBJO Gemmological Laboratories Book 2024

Treatment state
untreated
Qualification

In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Apatite, Scapolite, Topaz and other entries also name green or a greenish colour.

General note
colour alone is not identity
Source & check 2026-09-22
Source
Fact checked on
2026-09-22

How the sources relate

GB/T 16553—2017 and CIBJO Gemmological Laboratories Book 2024

complementary, no conflict

Both list green, purple, blue, yellow, colourless, pink and brown; the CIBJO Gemmological Laboratories Book also lists orange.

CIBJO definitions
colour change

Quality factors

Fluorite — quality factor (lustre): vitreous to subvitreous

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (locator checked 2026-09-21)
Fact checked on
2026-09-21

Each row's “Source & check” expands to the full source; the date beside it is the fact check date.

1.451.51.552.62.83Refractive indexSpecific gravity12345Fluorite

This material (RI / SG midpoints): 1.434 / 3.12; Closest values: 1Lapis Lazuli 1.5 / 2.75, 2Lepidolite 1.55 / 2.8, 3Serpentine 1.532 / 2.62, 4Albite 1.54 / 2.65, 5Brucite 1.57 / 2.89

Show the full chart (330 registered materials)1.41.51.61.71.81.922.12.22.32.41234567Refractive indexSpecific gravity12345Fluorite

Outside the full chart's range, drawn as triangles at the edge (RI / SG midpoints): Hematite 3.045/5.12, Synthetic Rutile 2.76/4.26, Rutile 2.753/4.23, Synthetic Moissanite 2.67/3.22

Refractive index × specific gravity (all registered materials)Each dot is one material's registered refractive index and specific gravity (range midpoints, not measurements); gold = this material, dark = the nearest few (picked on this site by distance in RI ÷ 0.02 and SG ÷ 0.1, leaving out near-identical varieties of the same species)Source: each material's registered refractive index and specific gravity facts (GB/T 16553 and others; sources on each entry)

Testing and market

The tests the CIBJO laboratory protocol requires for this material, and what each method means, are in the protocol table on the laboratory testing page: §6.1.35.

How far testing can go

Fluorite that has undergone irradiation can be identified by the following features: Colourless fluorite can be turned purple by irradiation; the colour fades easily in light and is very unstable. Fluorite with no phosphorescence can also be given phosphorescence by irradiation.

GB/T 16553—2017

Treatment state
irradiated or dyed
Does this standard apply
can be followed as a reference only
Treatment
irradiation
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (irradiation) (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite that has undergone filling can be identified by the following features: Under magnification the surface luster of the filled part differs from the host material and gas bubbles show in the filled area; infrared spectra show characteristic absorption bands of the filler; luminescence imaging (UV fluorescence viewer and similar) shows how the filler is distributed.

If a fluorescent agent was added during filling, the fissures show strong fluorescence and phosphorescence under long- and short-wave UV.

GB/T 16553—2017

Treatment state
treated
Does this standard apply
can be followed as a reference only
Treatment
filling
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (filling) (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite that has undergone heating can be identified by the following features: Black and dark blue fluorite is commonly heated to blue; the result is stable and not easy to detect.

GB/T 16553—2017

Treatment state
treated
Does this standard apply
can be followed as a reference only
Treatment
heating
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (heating) (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite that has undergone coating can be identified by the following features: Under magnification the surface luster is abnormal and the film can be seen peeling off in places; refractive index readings may be abnormal; infrared and Raman spectra show characteristic peaks of the film.

GB/T 16553—2017

Treatment state
treated
Does this standard apply
can be followed as a reference only
Treatment
coating
Source & check 2026-09-21
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.2.22 (coating) (locator checked 2026-09-21)
Fact checked on
2026-09-21

Fluorite — synthetic counterpart on the market: No synthetic counterpart of this material is commercially available

CIBJO Gemstone Book 2022

Treatment state
any treatment state
Source & check 2026-09-22
Source
Fact checked on
2026-09-22

Fluorite — what the CIBJO laboratory protocol says to watch for: fragile, easy cleavage

CIBJO Gemmological Laboratories Book 2024

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Fluorite — notes on test methods in the CIBJO laboratory protocol:

CIBJO laboratory protocol, in its own order; only the notes registered on this site
Test methodWhat the protocol notes for it
Phenomena: Colour-change

CIBJO Gemmological Laboratories Book 2024

Treatment state
any treatment state
Source & check 2026-09-26
Source
Fact checked on
2026-09-26

Each row's “Source & check” expands to the full source; the date beside it is the fact check date.

Clause-level definitions

Fluorite is listed directly as Fluorite in the gem materials list and definitions of CIBJO Gemmological Laboratories Book 2024, and the visible definition lists colours including green, purple, violet, blue, yellow, colourless, orange, pink and brown; the cross-check result is that it is defined directly by CIBJO and also appears in the GB/T annex. Blue John is defined directly in CIBJO Gemmological Laboratories Book 2024 under the entry name Blue John, as massive, with curved or angular bands of bluish violet to purple on a colourless background, transparent to translucent; the cross-check result is that it is defined directly by CIBJO, and no identically named English entry was found in the GB/T annex. The IMA Mineral List entry for Fluorite lists it as Fluorite with the chemical formula CaF2, cross-checked against the RRUFF/IMA master mineral list; the data are public domain.

This table scrolls sideways on narrow screens.

TermClauseDefinitionCross-check
Blue John7.2.1.31Massive, bluish violet to purple in curved or angular bands on a colourless background; transparent to translucentDefined directly by CIBJO; no identically named English entry was found in this edition of the GB/T annex.
Fluorite7.2.1.90Green, purple, violet, blue, yellow, colourless, orange, pink, brown; may show colour change of violet in daylight and red in incandescent light; transparent to translucentDefined directly by CIBJO; also present in the GB/T annex.
FluoriteIMA Mineral List entryFluorite CaF2 G ?Cross-checked against the RRUFF/IMA master mineral list (public domain data).

Evidence and sources

Authority basis and clause sources

GB/T 16552—2017
Listed Table A.2 “Fluorite” · Source
CIBJO Gemmological Laboratories Book 2024
Listed §7.2.1.90 “Fluorite” · Source
IMA Mineral List 2026-07
Listed “Fluorite” · Source

Sources

Further reading

Related pages

Treatments recorded for this material

Related entries and topic cluster

Parent entry and related pages on this site. Rows marked “Planned” are suggested new content and have no link yet.

This table scrolls sideways on narrow screens.

PageContentStatus
Browsing familyHalide mineralsLive
Treatments recorded for this materialHeated / Heat-treated, Filled / Fracture-filled, Coated, IrradiatedLive
Related articlesTo be added (placeholder)Planned

Who maintains this page

The material facts in the Fluorite entry are maintained by the LumaLark wiki and matched one by one to the standard clauses or institutional sources they cite: every fact carries its source (with a clause or page locator) and a check date, so it can be traced back to the original; clause-level definitions also carry a cross-check result. The entry exists so that buyers and sellers can check naming, disclosure and material facts item by item.

Facts editor
Ralph
Reviewer
June
How facts are checked
Each fact is matched to the clause it cites; facts checked between 2026-09-20 and 2026-09-26
Last revised
2026-10-12
Purpose
Lets buyers and sellers check naming, disclosure and material facts clause by clause.

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