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UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral group / supergroup · Natural identity; treatment status unknown
Apophyllite
A gem material name listed in Annex A.1 of GB/T 16552-2017; apophyllite is actually a mineral group name, so the specific species still needs identification. 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 Apophyllite forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- Caring for and wearing ApophylliteDurability indicators and wearing advice
- Hardness, density and refractive index of ApophylliteEach value with its source and check date
- Apophyllite 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 ApophylliteWhere the name comes from
- Listing and disclosing ApophylliteThe listing name to use; what must be disclosed before sale
- Standard clauses that define ApophylliteWhich 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
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.
'Apophyllite' names a mineral family rather than a single species. This record uses the family's representative species, fluorapophyllite (KCa4Si8O20(F,OH).8H2O), to describe origin: it is a secondary phase found in amygdules or druses within basalts, in granite cavities, in tactite and other metamorphic rocks, and, late in the hydrothermal sequence, in certain ore deposits. Fluorapophyllite and hydroxyapophyllite constitute a solid-solution series through F-OH substitution.
Scope: Applies to the identity definition of "apophyllite" as a mineral group/family name and to the genesis, composition and occurrence of the representative species within the group (fluorapophyllite); facts about the group name are not presented as facts about a single mineral species.
Sources Handbook of Mineralogy
Where it forms
Basalt amygdules and druses
Sources Handbook of Mineralogy
Cavities hosted by granite
Sources Handbook of Mineralogy
Tactite alongside other metamorphic rocks
Sources Handbook of Mineralogy
Late-stage hydrothermal settings in some ore deposits
Sources Handbook of Mineralogy
How it forms, step by step
After basalt or granite forms, later aqueous fluids enter amygdules, druses or cavities within the rock.
Sources Handbook of Mineralogy
Fluorapophyllite crystallizes as a secondary mineral in basalt amygdules/druses and granite cavities.
Sources Handbook of Mineralogy
It also crystallizes in tactite and other metamorphic rocks, or during the late hydrothermal stage of some deposits.
Sources Handbook of Mineralogy
Via F-OH substitution, fluorapophyllite forms a solid-solution series with hydroxyapophyllite.
Sources Handbook of Mineralogy
Link to appearance
Fluorapophyllite may be colorless, white, pink, pale yellow or green (colorless in thin section), with a vitreous luster and a pearly luster on {001}; crystals are commonly tabular to prismatic, pseudocubic, with deeply striated prism faces.
Sources Handbook of Mineralogy
Timescale
The source states no absolute geological timescale for apophyllite-group mineral formation.
Sources Handbook of Mineralogy
Supporting findings
Fluorapophyllite forms as a secondary phase within basalt amygdules or druses, in granite cavities, and, late in the hydrothermal sequence, in certain ore deposits.
Evidence grade BScope: Describes fluorapophyllite's secondary and hydrothermal occurrence; not the whole family.
Sources Handbook of Mineralogy
Fluorapophyllite also occurs in tactite and other metamorphic rocks, and is commonly associated with zeolites, datolite, pectolite, calcite and quartz.
Evidence grade BScope: Describes fluorapophyllite's metamorphic occurrence and typical associations; not all localities share them.
Sources Handbook of Mineralogy
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Asia
- Pune, Nashik and Mumbai districts, Maharashtra, IndiaExceptional crystal groups of fluorapophyllite
Sources Handbook of Mineralogy
Europe
- Teigarhorn, Berufjörður, Iceland
Sources Handbook of Mineralogy
South America
- Near Bento Gonçalves, Rio Grande do Sul, BrazilVery large crystals
Sources Handbook of Mineralogy
Seas and coasts
- WorldwideMany localities worldwide; Mindat lists 1,317 for the group
Sources Handbook of Mineralogy · Mindat: Apophyllite Group
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 the origin determination guide and the overview of recorded localities.
Where the name comes from
The etymology provided here applies to fluorapophyllite, the parent mineral, rather than to the trade name 'fish-eye stone'. That parent name records the abundance of fluorine in its composition, while apophyllite combines Greek words for 'away from' and 'leaf', referring to how the mineral flakes apart upon heating; the source offers no etymology for 'fish-eye stone' itself.
Evidence grade BScope: The etymology belongs to the parent mineral and does not establish the composition, locality, naturalness, or treatment of the material denoted by the trade name.
Sources Handbook of Mineralogy
Other research findings
'Apophyllite' is a mineral-group (family) name, not a single species; this record draws on the family's representative species fluorapophyllite.
Evidence grade BScope: Defines 'apophyllite' as a group name; identification of a specific sample requires determining the species.
Sources Handbook of Mineralogy
Fluorapophyllite has the formula KCa4Si8O20(F,OH).8H2O and forms a solid-solution series with hydroxyapophyllite (F-OH substitution).
Evidence grade BScope: Describes fluorapophyllite's composition and solid-solution relation; not every family member.
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 apophyllite-group entry, so this record uses the representative species fluorapophyllite as its basis.
- 'Apophyllite' is a family name, not a single species; the composition, colour and origin of a specific sample require identification to species level; the source also notes that distinguishing fluorapophyllite from hydroxyapophyllite needs chemical analysis.
- The source states no absolute geological timescale for apophyllite-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
- Apophyllite (state the specific mineral species)
GB/T 16552—2017 Table A.1 “Apophyllite”
Construction or treatment status
Natural identity; treatment status unknown
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
"Apophyllite" 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.1, row 鱼眼石 (Apophyllite)
What this means for you
Before buying, check the recommended listing name "Apophyllite (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
- Apophyllite (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
Toughness
Brittle
Daily wear
Fluorapophyllite ranks 4.5–5 on the Mohs scale, relatively soft and brittle with a perfect {001} cleavage; daily wear needs extra care to avoid scratching and impact.
Care
As a brittle material with cleavage, clean gently with warm, mild soapy water and a soft cloth; avoid ultrasonic and steam cleaners, sudden temperature changes, and impact or rubbing against hard objects.
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 properties of the material and does not constitute a durability or safety guarantee for any specific finished product; the durability of treated (filled/dyed/coated) or composite pieces must be assessed separately.
VerifyNames, standards, technical facts, clauses and sources
Names
Chinese standard nameThe Chinese formal name of Apophyllite is given in GB/T 16552—2017 Table A.1, the GSJ (Japan) formal name is written in kanji, and the mineralogical name is Apophyllite-group gem material. Names in four languagesThe names are given in Simplified Chinese, Traditional Chinese, English (Apophyllite) and Japanese. Institution usageOf GIA, FTC, CIBJO and Gem-A, the FTC and CIBJO texts on file have no wording for this name (checked), and GIA and Gem-A are unchecked; bodies without a recorded wording show the entry's own English name, Apophyllite, which does not represent their position. Recommended listing nameThe suggested listing name is Apophyllite (state the specific mineral species).
- GSJ (Japan) formal name
- 魚眼石
- Chinese formal name
- 鱼眼石 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Apophyllite-group gem material
Four-language names
- 简体中文
- 鱼眼石
- 繁體中文
- 魚眼石
- English
- Apophyllite
- 日本語
- 魚眼石／アポフィライト
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
What it is and how it's identified
Registered material facts for Apophyllite include: chemical composition KCa4Si8O20(F,OH)·8H2O; crystalline and tetragonal, with prismatic or tabular habit and pseudo-cubic crystals; Mohs hardness 4–5, with one set of perfect cleavage. Density is 2.3–2.5 g/cm³; the cited clause gives 2.40 with an allowed deviation of ±0.10, from which the displayed limits are derived. Optically it is anisotropic, uniaxial and negative; refractive index 1.535–1.537, birefringence 0.002. The UV-Vis spectrum is not diagnostic, and the mid-infrared region shows the characteristic infrared absorption bands of apophyllite. Untreated apophyllite has a vitreous to pearly lustre. This site also notes that hardness alone is not enough to judge durability.
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
Apophyllite — composition (chemistry): KCa4Si8O20 (F,OH) · 8H2O
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Structure
Apophyllite — structure (overall): crystalline
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — structure (crystal system): tetragonal
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — structure (crystal habit): columnar and tabular; pseudo-cubic crystals
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Durability
Apophyllite — Mohs hardness: 4–5
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — cleavage: perfect in one direction
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Physical properties
Apophyllite — density: 2.3–2.5 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 2.40, with a stated tolerance of ±0.10. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
Apophyllite — optic character: uniaxial, optically negative (anisotropic)
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — refractive index: 1.535–1.537
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — birefringence: 0.002
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — pleochroism: depends on the body color
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — fluorescence (long-wave UV): 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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — fluorescence (short-wave UV): none to weak, pale yellow
GB/T 16553—2017
UV fluorescence (short-wave UV)pale yellownone–weakDots are illustrative colours built from the colour names, not measured values
- 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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — 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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — spectrum (infrared): Apophyllite's diagnostic absorption bands appear 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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — magnification: gas-liquid inclusions, mineral inclusions, growth striations
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): §5.1.29 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Apophyllite — body colour: colorless, yellow, green, purple, pink-red, 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 Cultured Pearl, Scapolite, Apatite 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): §5.1.29 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Quality factors
Apophyllite — quality factor (lustre): vitreous to pearly
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): §5.1.29 (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): 1.536 / 2.4; Closest values: 1Haüyne 1.5 / 2.46, 2Balin Stone 1.56 / 2.55, 3Talc 1.569 / 2.5, 4Obsidian 1.495 / 2.4, 5Tektite / Moldavite 1.495 / 2.36
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
Clause-level definitions
In the clause-level definitions, Apophyllite is registered under the entry name Apophyllite, based on GB/T 16552-2017 Annex A, with the definition Apophyllite-group gem material. The cross-check result is that it is listed directly by GB/T, and CIBJO carries no standalone entry under the same name.
This table scrolls sideways on narrow screens.
| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Apophyllite | GB/T 16552-2017 Annex A | Apophyllite-group gem material | 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.
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Other silicate minerals | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Apophyllite 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.