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UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral species · Natural identity; treatment status unknown
Almandine
Also known asAlmandine Garnet · Almandite
A garnet-group mineral species with iron and aluminium as end-member components, known in English as almandine. 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 Almandine forms and what gives its colourFormation setting, process and timescale; where its colour and optical effects come from, each finding graded and sourced
- How to identify AlmandineHow far lab testing can go and whether a synthetic exists
- Treatments and enhancements of AlmandineThe enhancements and treatments the GB/T and JJA/AGL tables list
- Caring for and wearing AlmandineCleaning, heat, chemicals and light, as the cited sources give them
- Hardness, density and refractive index of AlmandineEach value with its source and check date
- Almandine in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name; and: Which of GIA, FTC, CIBJO and Gem-A have a name for it on record, and do those agree?
- Listing and disclosing AlmandineThe listing name to use
- Standard clauses that define AlmandineWhich 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
Almandine is the aluminium garnet species that carries iron, with Fe occupying the dodecahedral site as the end member. Its iron-rich red material ranks among the most abundant and widely spread of gems, appearing on every continent in rocks that heat and pressure have recrystallised. Members of the garnet group keep essentially one crystal framework but vary in chemistry; almandine frequently enters solid solution with pyrope and spessartine, an example being the almandine–pyrope–spessartine series generated where pressure is high and burial deep. Because a single gem is commonly a blend of two or more garnet species, the name ‘almandine’ marks an end-member composition and not a strictly pure substance.
Scope: Used to describe the occurrence and composition of almandine as a garnet end-member mineral species; the source does not give formation temperatures, pressures or ages for specific localities.
Sources GIA Garnet Description · G&G Summer 2025 · G&G Fall 2016
Where it forms
Metamorphic rocks (altered by heat and pressure): the principal host of the iron-rich red almandine-pyrope garnets.
Sources GIA Garnet Description · G&G Summer 2025
Deep high-pressure settings: the almandine-pyrope-spessartine solid solution forms at high pressure deep in the earth.
Sources GIA Garnet Description · G&G Summer 2025
How it forms, step by step
Under metamorphic conditions or deep high pressure, suitable bulk-rock chemistry promotes garnet-group crystallization.
Sources GIA Garnet Description · G&G Summer 2025
Because the structures are similar, the lattice accommodates different divalent cations (Fe, Mg, Mn), producing almandine-pyrope-spessartine solid solutions.
Sources GIA Garnet Description · G&G Summer 2025
In iron-rich systems the almandine component dominates, giving the widespread red almandine-pyrope garnets.
Sources GIA Garnet Description · G&G Summer 2025
Link to appearance
Electronic transitions of Fe2+/Fe³⁺ dominate absorption, giving red to purplish-red; the purple (rhodolite) tone arises from Fe and minor Mn absorption bands.
Sources GIA Garnet Description · G&G Fall 2016
Timescale
The sources state no absolute age or duration for garnet formation.
Sources GIA Garnet Description · G&G Summer 2025 · G&G Fall 2016
Related base materials
- Garnet group: mineral-group member | Almandine is the garnet mineral species with Fe2+ occupying the dodecahedral site, and commonly forms solid solutions with pyrope/spessartine
Supporting findings
Red almandine(-pyrope) garnet is among the most common and widespread gems, found in metamorphic rocks on every continent.
Evidence grade AScope: Concerns iron-rich red garnets (almandine-pyrope); not all garnet species.
Sources GIA Garnet Description
This almandine–pyrope–spessartine solid-solution series is generated at high pressure, deep within the earth.
Evidence grade AScope: Refers to the star-garnet almandine-pyrope-spessartine series; not the calcium garnets.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Agere Maryam, Sidamo, Ethiopiacombined almandine/rhodolite column of the G&G 2000s table
Sources Gems & Gemology Fall 2010
Europe
- Zillertal, Tyrol, Austria
Sources Handbook of Mineralogy
North America
- Barton mine, North Creek, Warren County, New York, United StatesHoM calls it a large commercial deposit (use not stated)
Sources Handbook of Mineralogy
Seas and coasts
- Worldwide
Sources Handbook of Mineralogy
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
The purple (rhodolite) garnet colour arises from Fe2+/Fe³⁺ absorption with a weak Mn2+ peak near 408 nm.
Evidence grade AScope: Based on Mozambique purple pyrope-almandine samples; other localities may differ.
Sources G&G Fall 2016
Other research findings
Almandine counts as one species within the garnet group, and a great many garnet stones are in fact blends of two or more such species.
Evidence grade AScope: Places almandine within the group and its solid-solution nature; not a pure single end member.
Sources GIA Garnet Description
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- Sources are a GIA encyclopedia entry and case studies; no absolute age, P-T or deposit-wide data for almandine formation.
- No evidence for magmatic/pegmatitic (non-metamorphic) settings is covered.
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
- Almandine
GB/T 16552—2017 Table A.1 “Almandite” · CIBJO Gemmological Laboratories Book 2024 §7.2.1.7 “Almandine”
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Heated / Heat-treated (via parent material), Filled / Fracture-filled (via parent material)
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
Almandine is Almandine garnet; use "Almandine" for listings, and disclose any known treatments.
What this means for you
Before buying, check the recommended listing name "Almandine" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.
- 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.
The item-by-item care advice that the GIA Care and Cleaning Guide gives for the whole class, and so for Almandine, is set out in full under care on the Garnet entry.
Care
Almandine — care (heat): Some stones are prone to damage due to thermal shock. Do not expose them to extreme temperature changes.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code e
- Treatment state
- any treatment state
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, Almandine, p.54; §6.2 e (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Almandine — care (special care): normal care, but avoid sudden temperature change.
AGTA Gemstone Information Manual, 17th ed.
- Treatment state
- untreated
Source & check 2026-09-26
- Source
- AGTA Gemstone Information Manual, 17th edition (August 2026) (AGTA): p.X, Gemstone Information Chart, Garnet Almandite N, CARE REQUIRED / SPECIAL ADVICE (locator checked 2026-09-26)
- 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
HeatThe care conclusion for Almandine on heat and thermal shock is that it is sensitive to sudden temperature changes. The CIBJO Blue Book — Official Gemstone Book (2022), covering any treatment state, states that Almandine is sensitive to sudden temperature changes. The AGTA Gemstone Information Manual, 17th edition, covering untreated stones, says normal care is sufficient but sudden temperature changes should be avoided. General careThe GIA care and cleaning guide is given for the whole class and also applies to Almandine; its item-by-item advice is listed in full in the care section of the Garnet entry, and the full table of general care and special care letter codes that applies to all gems is in the general care part of the materials index page.
This table scrolls sideways on narrow screens.
| Question | Matching entries |
|---|---|
| Heat and thermal shock | care (heat) |
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
- care (heat) §6.2 e
untreated
Treatments and identification leads
One row per treatment, with three standards side by side: how often it occurs and how stable it is (CIBJO), its category in GB/T 16552—2017 Table B.1 (this site's paraphrase) and how the JJA/AGL 2025 table lists it. Each CIBJO value links to its entry under “Testing and market”, where the wording and source are given in full.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| Heating | — | — | Optimization | — | — |
| Filling | — | — | Graded — see §5.4.1, Table 1 | — | — |
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16552—2017 Table B.1 (row for Garnet); 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 Almandine, the name register records "Almandine Garnet" and "Almandite", for which no restriction on use as a name is recorded (JJA/AGL Gemstone Nomenclature 2025 p.9); 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 GB/T 16552—2017 formal name for Almandine is the Chinese name listed in Table A.1, and the suggested listing name is that formal name, Almandine; known treatments must be disclosed. Names in four languagesFour-language names are given in Simplified Chinese, Traditional Chinese, English (Almandine) and Japanese, and the formal name of Japan's GSJ is written as a separate Japanese term; the mineralogical name is Almandine garnet, and the trade name/synonym is Almandite. Institution usageOn authority wording, CIBJO records Almandine (CIBJO Gemmological Laboratories Book 2024), the FTC text on file has 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, which does not represent the position of GIA or Gem-A. Candidate search termsIn the name register, Almandine Garnet is a synonym (per the JJA/AGL gem name handbook 2025), a Japanese katakana form of almandine garnet is a transliteration kept only as a candidate search term, and Almandite is an older name as ruled by this site.
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.
| Name | Type | Matching | Use as a name | Basis |
|---|---|---|---|---|
| no restriction recorded (3) | ||||
| Almandine GarnetEnglish | synonym | matched automatically | no restriction recorded | JJA/AGL Gemstone Nomenclature 2025 p.9 |
| AlmanditeEnglish | historical name | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
| アルマンディン・ガーネットJapanese | transliteration | search candidate only | no restriction recorded | JJA/AGL Gemstone Nomenclature 2025 p.9 |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- 鉄礬石榴石
- Chinese formal name
- 铁铝榴石 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Almandine garnet
- Trade names and synonyms
- Almandite (historical name) · Almandine Garnet (synonym)
Four-language names
- 简体中文
- 铁铝榴石
- 繁體中文
- 鐵鋁榴石
- English
- Almandine
- 日本語
- アルマンディン
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Garnet-group minerals and gem varieties
- Identity tier
- Mineral species
- Mineral chemical class
- Silicates
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
GB/T 16552-2017, Annex B, Table B.1
Under the “Garnet” row of Table B.1: Heating Optimization; Filling Graded — see §5.4.1, Table 1. The full row, with the effect column, is on the Garnet page.
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 name | Species | Colour | Listed in the table | Notes |
|---|---|---|---|---|
| Almandine Garnet | Almandine | deep red to purplish red | an untreated tier is listed |
JJA/AGL definitions and nomenclature (2025 revision), table of principal gem names, p.9
How to read the JJA/AGL table: see the Gem treatments page.
What it is and how it's identified
Among the material facts for Almandine, density and refractive index are listed from clause values for Almandine itself, while structure, hardness, cleavage, optic character, birefringence and lustre are registered from clauses for garnet (the whole mineral group) and are not measured on Almandine separately. The composition (phase) of Almandine is almandine (garnet group); for the garnet group, the structure is crystalline and cubic, Mohs hardness is 7–8, and there is no cleavage. The density of 3.93–4.3 g/cm³ and refractive index of 1.76–1.82 for Almandine are both derived from the cited clause values plus permitted tolerances: a density clause value of 4.05 with a tolerance of +0.25/−0.12, and a refractive index clause value of 1.790 with a tolerance of ±0.030. For the garnet group, the optic character is isotropic, commonly with anomalous extinction, and there is no birefringence; when untreated, the lustre is vitreous to subadamantine. Asterism may occur according to CIBJO; according to GB/T, six-rayed stars are occasionally seen; for the garnet group, asterism is visible but rare, generally as four-rayed stars and occasionally as six-rayed stars.
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”.
Chemical composition, luminescence, UV-visible spectrum, infrared spectrum, magnification: these whole-class features are given in the cited clause for garnet (the whole mineral group), so they are not repeated on the Almandine page; see the material facts on the Garnet entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Almandine (how to read class-level values).
Definition
Almandine — 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
Almandine — composition (phase): almandine (garnet group)
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Structure
Almandine — structure (overall): crystalline
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Almandine — structure (crystal system): cubic
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Almandine — structure (crystal habit): rhombic dodecahedra, tetragonal trisoctahedra, or crystals combining the two forms.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
Almandine — Mohs hardness: 7–8
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
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Almandine — cleavage: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Almandine — density: 3.93–4.3 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 4.05, with a stated tolerance of +0.25 / -0.12. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 Density · Almandine (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Almandine — density: 3.5–4.3 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
- General note
- the clause has finer ranges
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Almandine — optic character: isotropic, commonly with anomalous extinction
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Almandine — refractive index: 1.76–1.82
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- Qualification
The clause we cite gives 1.790, with a stated tolerance of ±0.030. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 Refractive index · Almandine (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Almandine — birefringence: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Almandine — transparency: transparent and translucent.
CIBJO Gemmological Laboratories Book 2024
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Almandine — pleochroism: none
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Almandine — spectrum (UV-visible): 504 nm strong absorption band; 520 nm strong absorption band; 573 nm strong absorption band; 423 nm weak absorption band; 460 nm weak absorption band; 610 nm weak absorption band; 680~690 nm weak absorption band.
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): §5.1.15 UV-visible spectrum (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
optical effect (asterism)2 sources compared
Almandine — optical effect (asterism): asterism.
CIBJO Gemmological Laboratories Book 2024
- Qualification
The cited source states that this effect may occur.
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Almandine — optical effect (asterism): A six-rayed star is occasionally seen
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): §5.1.15 Special optical effects (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Almandine — optical effect (asterism): seen; rare; generally a four-pointed star; occasionally a six-rayed star (almandine).
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Almandine — optical effect (colour change): seen
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
body colour2 sources compared
Almandine — body colour: Reddish purple to slightly purplish red; reddish orange to red.
CIBJO Gemmological Laboratories Book 2024
- Treatment state
- untreated
- Qualification
In chapter 7 of the CIBJO Gemmological Laboratories Book, the colour descriptions of Pyrope, Ruby, Red Beryl and other entries also name purple or a purplish colour.
- General note
- colour alone is not identity
Source & check 2026-09-22
- Source
- Fact checked on
- 2026-09-22
Almandine — body colour: orange-red to red, purplish red to reddish purple; darker in tone.
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 Ruby, Sugilite, Zircon and other variety clauses also name red or a reddish colour.
- General note
- colour alone is not identity
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 Colour · Almandine (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
How the sources relate
- CIBJO Gemmological Laboratories Book 2024 and GB/T 16553—2017
Both cover the band between red and purple (GB/T 16553—2017: purplish red to reddish purple; the CIBJO Gemmological Laboratories Book: reddish purple to slightly purplish red), and both include an orange-leaning red. GB/T 16553—2017 adds that the tone is darker.
- CIBJO definitions
- asterism, colour change
Quality factors
Almandine — quality factor (lustre): vitreous to subadamantine
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- garnet (the whole mineral group)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.15 (locator checked 2026-09-26)
- 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.
This material (RI / SG midpoints): 1.79 / 3.9; Closest values: 1Spessartine 1.802 / 3.9, 2Burma Ruby 1.768 / 4, 3Ceylon Sapphire 1.768 / 4.03, 4Garnet 1.825 / 3.9, 5Rhodolite 1.755 / 3.9
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
Almandine is a mineral species of the garnet group. The CIBJO laboratory protocol places Almandine under “Garnet”: for how Almandine is identified, see the identification section of the Garnet entry, and for the list of required tests, see the laboratory testing page. As for synthetics, no synthetic Almandine is available on the market.
The CIBJO laboratory protocol covers Almandine under “Garnet” (§6.1.38): see identification on the Garnet entry; the required tests are listed on the CIBJO laboratory protocol table for Garnet.
How far testing can go
Almandine — 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
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Clause-level definitions
Almandine is defined directly in the CIBJO Gemmological Laboratories Book 2024 under the entry Almandine: a material that is transparent and translucent, usually dark in tone, with colours from reddish purple to slightly purplish red and from reddish orange to red. The cross-check result is a direct CIBJO definition; no identically named English entry was found in this edition of the GB/T annex. The IMA Mineral List entry gives the chemical formula Fe2+3Al2(SiO4)3 and IMA status G, cross-checked against the RRUFF/IMA master mineral list (public domain data).
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Almandine | 7.2.1.7 | Reddish purple to slightly purplish red; reddish orange to red, transparent and translucent, typically dark in tone; may show asterism | Defined directly by CIBJO; no identically named English entry was found in this edition of the GB/T annex. |
| Almandine | IMA Mineral List entry | Almandine Fe2+3Al2(SiO4)3 G 1546 | Cross-checked against the RRUFF/IMA master mineral list (public domain data). |
Evidence and sources
Authority basis and clause sources
Sources
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 | Garnet-group minerals and gem varieties | Live |
| Treatments recorded for this material | Heated / Heat-treated (via parent material), Filled / Fracture-filled (via parent material) | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Almandine 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.