On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral group / supergroup · Natural identity; treatment status unknown
Chlorite
A name listed in GB/T 16552-2017 Appendix A.2; Chlorite refers to a group of minerals rather than a single species, and the specific species must be identified. 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.
What this page can answer
This page covers
- How Chlorite forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify ChloriteHow far lab testing can go
- Treatments and enhancements of Chlorite1 registered treatments: status, stability, how common they are and identification leads
- Caring for and wearing ChloriteDurability indicators and wearing advice
- Hardness, density and refractive index of ChloriteEach value with its source and check date
- Chlorite in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name; and: Has any of GIA, FTC, CIBJO or Gem-A put a name for it on record here?
- Name origin and history of ChloriteWhere the name comes from
- Listing and disclosing ChloriteThe listing name to use; what must be disclosed before sale
- Standard clauses that define ChloriteWhich clause defines it, each cross-checked
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
The name "chlorite" denotes a family, or mineral group, rather than one species; its members are sheet silicates. To describe the origin, this record relies on two Handbook of Mineralogy species that stand for the family: clinochlore, at the magnesium-rich end, and chamosite, at the iron-rich end. Biotite, pyroxenes and amphiboles subjected to hydrothermal alteration yield clinochlore, which is found in amphibolites, calc-silicate rocks, marbles, serpentinites and chlorite schists. Chamosite, by contrast, is generated authigenically within sedimentary ironstones where reducing conditions prevail and decomposed organic matter is present. Between them, clinochlore and chamosite define an Mg-Fe solid-solution series.
Scope: Applies to the identity definition of "chlorite" as a mineral group/family name and to the genesis, composition and occurrence of representative species within the group (clinochlore, chamosite); facts about the group name are not presented as facts about a single mineral species.
Sources Handbook of Mineralogy
Where it forms
Chlorite schists, serpentinites, marbles, calc-silicate rocks, amphibolites (clinochlore)
Sources Handbook of Mineralogy
Within ironstones of sedimentary type, chamosite forms under reducing conditions
Sources Handbook of Mineralogy
Hydrothermal alteration zones and ore veins
Sources Handbook of Mineralogy
How it forms, step by step
Mg-Fe-bearing rocks undergo hydrothermal alteration, converting amphiboles, pyroxenes and biotite into clinochlore.
Sources Handbook of Mineralogy
Clinochlore occurs in chlorite schists, serpentinites, marbles, calc-silicate rocks and amphibolites.
Sources Handbook of Mineralogy
Within sedimentary ironstones chamosite is generated authigenically, in reducing conditions created by organic material that has decomposed.
Sources Handbook of Mineralogy
Clinochlore and chamosite form an Mg-Fe solid-solution series, with stacking disorder being common.
Sources Handbook of Mineralogy
Link to appearance
Chlorite-group minerals are typically grass-green, olive-green, yellowish or white, also pink to rose-red (clinochlore); chamosite may be green, greenish grey, black or brown. They commonly form foliated to scaly aggregates with a pearly, greasy or dull luster, and their cleavage laminae are flexible but inelastic.
Sources Handbook of Mineralogy
Timescale
The sources state no absolute geological timescale for chlorite-group mineral formation.
Sources Handbook of Mineralogy
Supporting findings
Clinochlore arises as a product of hydrothermal alteration acting on biotite, pyroxenes and amphiboles; it is found in amphibolites, calc-silicate rocks, marbles, serpentinites and chlorite schists.
Evidence grade BScope: Describes the hydrothermal origin of clinochlore (not the whole family).
Sources Handbook of Mineralogy
Chamosite forms authigenically in sedimentary ironstones under reducing conditions caused by decomposed organic material; clinochlore and chamosite form a solid-solution series.
Evidence grade BScope: Describes chamosite's sedimentary origin and the two species' solid-solution relation; not the whole family.
Sources Handbook of Mineralogy
Where the name comes from
The cited sources give no etymology for 'chlorite' as a group name. The origins they do supply are those of representative species: clinochlore alludes both to its inclined optic axes and to the Greek chloros, meaning green, the colour it typically shows; chamosite refers to the locality at Chamoson, Switzerland. These origins belong to the species, not to the group name chlorite.
Evidence grade BScope: The etymology explains the origin of a name only; it does not attest composition, locality, naturalness or treatment, and here belongs to the parent mineral rather than to the trade name itself.
Sources Handbook of Mineralogy
Other research findings
'Chlorite' is a mineral-group (family) name, not a single species; this record draws on the family's two representative species clinochlore and chamosite.
Evidence grade BScope: Defines 'chlorite' as a group name; identification of a specific sample requires determining the species.
Sources Handbook of Mineralogy
Clinochlore has the formula (Mg,Fe2+)5Al(Si3Al)O10(OH)8 and chamosite (Fe2+,Mg,Fe3+)5Al(Si3Al)O10(OH,O)8; both belong to the chlorite group.
Evidence grade BScope: Describes two representative species; not the whole compositional range of the family.
Sources Handbook of Mineralogy
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- The Handbook of Mineralogy has no separate chlorite-group entry, so this record uses the two representative species clinochlore and chamosite as its basis.
- 'Chlorite' is a family name, not a single species; the composition, colour and origin of a specific sample require identification to species level.
- The sources state no absolute geological timescale for chlorite-group mineral formation.
Methodology
- Origin determination and its limits
- Quality grading and value factors
- How gemmology became a technical discipline
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
- Chlorite (state the specific mineral species)
GB/T 16552—2017 Table A.2 “Chlorite” · CIBJO Gemmological Laboratories Book 2024 7.1.2
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Dyed
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
"Chlorite" is a market name rather than a mineral species name; before using it, verify: Industry-wide term that does not denote a single species.
Evidence
- GB/T · Table A.2, row 绿泥石 (Chlorite)
What this means for you
Before buying, check the recommended listing name "Chlorite (state the specific mineral species)" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.
Known uncertainty
- This entry's exact material identity is not fully settled.
- See “Disclosure and cautions” above
- Last reviewed
- 2026-09-01
Trade-name ruling
- Industry-wide term that does not denote a single species.
- Suggested listing name
- Chlorite (state the specific mineral species)
Care and wear
No institutional care guidance is registered for this material yet; below are its durability indicators and general guidance.
Durability and wearing
Numbers in curly braces, such as {111}, are crystallographic face symbols (Miller indices): each marks a set of crystal faces or cleavage planes. They are reproduced as written in the cited source.
Toughness
Laminae flexible, inelastic
Sources Handbook of Mineralogy
Daily wear
Only Mohs 2–2.5 with perfect {001} cleavage and flexible-but-inelastic laminae; it is very soft, easily scratched and cleaves into sheets, and is normally a display/industrial material rather than daily-wear.
Care
Wipe with a dry soft cloth and avoid rubbing, soaking and bending; never scrape with hard objects or use ultrasonic cleaning (basis: source records perfect {001} cleavage and Mohs 2–2.5).
General guidance: LumaLark's general guidance inferred from the material's properties (hardness, toughness, cleavage); not text from the cited source, and not a guarantee for any specific piece.
Scope: This field describes the general physical properties of chlorite as a material; it makes no durability or safety promise for any specific finished product. Durability of treated (e.g. filled, dyed, coated) or assembled/composite pieces must be assessed separately for the individual item.
Treatments and identification leads
Registered treatmentsThe registered treatment for Chlorite is dyeing. Values not givenDyeing has the status colour-treated; its stability and prevalence are both recorded as “—”, meaning the cited source gives no value, not “none”. To identify dyed Chlorite: under magnification the colour is unevenly distributed, with the dye often gathered in fractures, grain boundaries or surface pits; under long-wave and short-wave UV the dye may show distinctive fluorescence; and composition analysers such as XRF can detect foreign elements introduced by the dye, for example Pb. Identification cluesThe identification leads come from GB/T 16553—2017; for dyed Chlorite, GB/T 16553—2017 serves only as a reference and does not govern it directly.
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| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| dyeingStatus: colour treated | — | — | Treatment | — | See identification leads |
Where each treatment acts (schematics): Dyed
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16553—2017; GB/T 16552—2017 Table B.1
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
Standard and listing namesThe GB/T 16552—2017 formal name of Chlorite is given in Table A.2, and the mineralogical name is Chlorite-group minerals; Chlorite is a general trade name, not a mineral species name, and does not refer to a single species, so the suggested listing name is Chlorite (state the specific mineral species). Names in four languagesThe four-language names are the Simplified and Traditional Chinese names, English Chlorite and the Japanese names. The entry carries its own Japanese name, but the GSJ (Japan) wording for this name is not yet verified by this site. Institution usageFor authority wording, the FTC text on file has no wording for Chlorite (checked); GIA, CIBJO and Gem-A are unchecked.
- GSJ (Japan) formal name
- クロライト／緑泥石 (not yet checked for this body — the entry's own Japanese name is shown)
- Chinese formal name
- 绿泥石 (GB/T 16552—2017 Table A.2)
- Mineralogical name
- Chlorite-group minerals
Four-language names
- 简体中文
- 绿泥石
- 繁體中文
- 綠泥石
- English
- Chlorite
- 日本語
- クロライト／緑泥石
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Other silicate minerals
- Identity tier
- Mineral group / supergroup
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
Chlorite is listed under the "Chlorite" row of GB/T 16552—2017 Annex B, Table B.1 with one method, dyeing, which changes colour, category treatment. The explanation of Table B.1 and the definitions of each grade are on the Gem treatments page.
GB/T 16552-2017, Annex B, Table B.1
Table B.1, row “Chlorite” (p.17):
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| Method | Effect | Category |
|---|---|---|
| Dyeing | Changes colour | Treatment |
What Table B.1 is, and how the “see 5.4.1” grades are defined: see the GB/T 16552: optimization vs treatment page.
What it is and how it's identified
The material facts for Chlorite are registered from GB/T 16553—2017: composition (Mg,Fe,Al)3(OH)6{(Mg,Fe,Al)3[(Si,Al)4O10](OH)2}; structure crystalline aggregate, commonly granular or scaly; Mohs hardness 2–3, with the site's general note that hardness alone is not enough to judge durability; cleavage usually not visible in aggregates; density 2.6–3.4 g/cm³; optical character anisotropic aggregate; refractive index 1.572–1.685, where the site note explains that the clause has finer sub-ranges and the overall value is registered; birefringence not measurable on an aggregate. Untreated Chlorite has body colours including colourless, greyish white, light yellow and light to dark green, with colour changing with composition, and its lustre is vitreous to earthy; the site's qualifying note explains that the colour descriptions in the clauses for albite jade, hemimorphite, iolite and other varieties in chapter 5 of GB/T 16553—2017 also mention colourless.
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
Chlorite — composition (chemistry): (Mg,Fe,Al) 3 (OH) 6{ (Mg,Fe,Al) 3[ (Si,Al) 4O10] (OH) 2}.
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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Structure
Chlorite — structure (overall): crystalline aggregate, usually of grains and scales.
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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Chlorite — Mohs hardness: 2–3
GB/T 16553—2017
Reference points on this site: Talc 1–3, Fluorite 4, 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))
- Does this standard apply
- applies to this entry
- General note
- hardness only, not durability
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Chlorite — cleavage: generally not seen on an 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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Chlorite — density: 2.6–3.4 g/cm³
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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Chlorite — optic character: anisotropic 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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Chlorite — refractive index: 1.572–1.685
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- General note
- the clause has finer ranges
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Chlorite — birefringence: not measurable on an 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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Chlorite — pleochroism: not measurable on an aggregate
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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Chlorite — fluorescence (overall): generally 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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Chlorite — 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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Chlorite — spectrum (infrared): diagnostic bands of chlorite in the mid-IR
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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Chlorite — magnification: granular or scaly structure, compact massive 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): §5.2.40 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Chlorite — body colour: colorless, greyish white or pale yellow, and pale to deep green; color changes with composition.
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 Albite Jade, Hemimorphite, Iolite and other variety clauses also name colourless.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.40 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Quality factors
Chlorite — quality factor (lustre): vitreous to earthy
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): §5.2.40 (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.
This material (RI / SG midpoints): 1.629 / 3; Closest values: 1Brazilianite 1.611 / 2.97, 2Datolite 1.646 / 2.95, 3Dushan Yu / Dushan Jade 1.63 / 2.9, 4Amblygonite 1.607 / 3.02, 5Lazulite 1.627 / 3.12
Show the full chart (330 registered materials)
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
Testing and market
The identification leads for dyed Chlorite are: under magnification the colour is unevenly distributed, with the colorant tending to gather in fractures, grain boundaries or surface pits; under long-wave and short-wave UV the dye may give a distinctive fluorescence; and a chemical analyser such as XRF can detect foreign elements introduced by the dye, such as Pb. The status for dyeing is colour-treated; the cited GB/T 16553—2017 serves only as a reference for the chlorite entry and does not govern it directly.
How far testing can go
Chlorite that has undergone dyeing can be identified by the following features: Under magnification the colour is unevenly distributed and mostly concentrated in fissures, between grains or in surface hollows; the dye may respond to long- and short-wave UV with an unusual fluorescence; compositional analysis (XRF and similar) detects foreign elements of the dye such as Pb.
GB/T 16553—2017
- Treatment state
- colour treated
- Does this standard apply
- can be followed as a reference only
- Treatment
- dyeing
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.2.40 (dyeing) (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.
Clause-level definitions
At the clause level, Chlorite is defined under the term Chlorite, based on GB/T 16552-2017 Annex A, with the definition Chlorite-group minerals; the cross-check shows it is listed directly by GB/T, and CIBJO carries no standalone entry under the same name.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Chlorite | GB/T 16552-2017 Annex A | Chlorite-group minerals | Listed directly by GB/T; CIBJO carries no standalone entry under the same name. |
Evidence and sources
Authority basis and clause sources
Sources
- CIBJO – The World Jewellery Confederation. Gemmological Laboratories Book (Blue Book), Gemmological Commission 2024-1.
- CIBJO – The World Jewellery Confederation. The Gemstone Book (Blue Book), 2022.
- SAMR / SAC (China). GB/T 16552—2017 Gems — Nomenclature.
- RRUFF Project, in partnership with the IMA – International Mineralogical Association. IMA Mineral List.
- Geological Survey of Japan, AIST (Japan). Museum mineral specimens, browse by classification.
Further reading
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.
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| Page | Content | Status |
|---|---|---|
| Browsing family | Other silicate minerals | Live |
| Treatments recorded for this material | Dyed | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Chlorite 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.