On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural inorganic gem materials · Mineral / gemstone variety · Natural identity; treatment status unknown
Fancy Color Diamond
Also known asFancy Colour Diamond
Diamond whose colour falls in the GB/T 16553 "fancy colour series": yellow, brown, grey and light to deep blue, green, orange, pink, red, purplish red, black and others, as opposed to the "colourless to light yellow (brown, grey) series". Also known as Fancy Colour Diamond.
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 Fancy Color Diamond 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 Fancy Color DiamondIdentification points from the research literature; how far lab testing can go
- Treatments and enhancements of Fancy Color Diamond1 registered treatments: status, stability, how common they are and identification leads
- Hardness, density and refractive index of Fancy Color DiamondEach value with its source and check date
- Fancy Color Diamond 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 Fancy Color DiamondThe listing name to use; what must be disclosed before sale
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
A fancy-colour diamond is a colour variety of diamond rather than an independent mineral species; its parent material is diamond. Within the normal colour range diamonds run from colourless through light yellow and are described using the D-to-Z scale, while fancy colour diamonds are those yellow or brown stones whose colour falls outside (beyond) Z, or any diamond showing some other colour when viewed face-up. The source cited for this entry gives no general colour-cause mechanism, so NOTE: the colour origin of a fancy colour diamond must be determined on a stone-by-stone basis in the laboratory and cannot be generalised; this entry makes no blanket assertion about any specific stone's colour cause.
Scope: Applies to defining the identity of fancy colour diamonds as the coloured series of diamond varieties and an overview of their colour range; the colour origin must be determined by a laboratory piece by piece, and this record makes no uniform assertion. Synthetic (laboratory-grown) or treated diamonds are not covered.
Sources GIA Fancy Color Diamond Description
Where it forms
Parent-diamond setting (not specific to fancy colours): at about 100 miles depth beneath Earth's surface, under high temperature and pressure.
Sources GIA Fancy Color Diamond Description
NOTE: the cited source does not describe colour-specific formation steps; colour origin requires stone-by-stone laboratory determination.
Sources GIA Fancy Color Diamond Description
How it forms, step by step
The parent diamond forms at about 100 miles depth beneath Earth's surface, under high temperature and pressure unique to that depth range (a parent-material fact).
Sources GIA Fancy Color Diamond Description
Where colour-relevant factors are present, a diamond's colour falls beyond the D-to-Z normal range, or it shows another colour face-up, making it a fancy colour diamond.
Sources GIA Fancy Color Diamond Description
NOTE: the cited source gives no general colour-cause mechanism; a specific stone's colour cause requires laboratory determination, so no formation steps are invented.
Sources GIA Fancy Color Diamond Description
Link to appearance
Fancy colour diamonds display nearly every hue of the spectrum. Rarest by far are red, green, purple and orange; next come pink and blue, while yellow and brown are by far the most plentiful; black, grey and fancy white diamonds likewise belong to the fancy category. Naturally coloured fancies are typically not deeply saturated, and their worth tends to rise with the intensity and purity of the hue. NOTE: the cause of a given colour has to be established for each stone in the laboratory and cannot be read off from appearance alone.
Sources GIA Fancy Color Diamond Description
Timescale
The source states no absolute geological timescale for the formation of fancy colour diamonds (or of their colour).
Sources GIA Fancy Color Diamond Description
Related base materials
- Diamond: Fancy colour diamond is the coloured range of varieties of diamond; its parent material is diamond, and it is not an independent mineral species.
Recorded localities
Authoritative sources list the localities below; the list is not exhaustive.
Africa
- Cullinan mine, Gauteng, South AfricaSpecific source for blue, gray and violet diamonds
Sources Gems & Gemology Summer 2018
Oceania
- Argyle mine, Western Australia, AustraliaSource of pink to red diamonds; closed in 2020
Sources Gems & Gemology Winter 2014 · Gems & Gemology Fall 2024
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
NOTE: the cited source gives no general colour-cause mechanism for fancy colour diamonds; their colour origin must be determined on a stone-by-stone basis in the laboratory and cannot be generalised, so this entry makes no blanket assertion.
Evidence grade AScope: A cautious statement where the source lacks a colour-cause mechanism; does not speculate on any specific stone's chromophore.
Sources GIA Fancy Color Diamond Description
How it is identified
The appearance of a fancy-colour or treated diamond cannot establish whether it is natural, synthetic or treated. Separation rests on measurable properties and the division of labour between instruments: magnification reveals inclusions, colour zoning and graining (growth striations) (graining that follows the octahedral planes indicates natural); long- and short-wave ultraviolet fluorescence shows the fluorescence pattern (natural diamonds usually fluoresce an even blue, synthetic ones usually yellow-green and often more strongly to short wave); in spectroscopy a 415 nm 'Cape' line can prove natural origin, while synthetic stones show nickel-related absorption lines; attraction of metallic flux inclusions to a strong magnet proves synthetic; and strain patterns under crossed polarizers also help. Advanced methods include cathodoluminescence, EDXRF chemical analysis and infrared spectroscopy, plus time-gated luminescence imaging (DiamondView-type instruments) and automated screening devices. Limitations: high-clarity diamonds free of inclusions often lack clear diagnostic features and melee is harder still, so the conclusion must be issued by an accredited gemological laboratory through testing.
Evidence grade AScope: Identification and separation points; testing must be performed by an accredited gemological laboratory, and no self-test thresholds are given.
Other research findings
A fancy colour diamond is a colour variety of diamond rather than an independent mineral species: within the normal range diamonds are colourless through light yellow (D-to-Z scale), while fancy colour diamonds are yellow and brown diamonds exhibiting colour beyond the Z range, or diamonds exhibiting any other colour face-up.
Evidence grade AScope: Defines the variety status and colour-definition range; not an independent mineral species.
Sources GIA Fancy Color Diamond Description
Fancy colour diamonds display almost every hue imaginable; the rarest are red, green, purple and orange, then pink and blue, whereas yellow and brown are the most abundant. Black, grey and fancy white stones also count as fancies.
Evidence grade AScope: Describes colours and a qualitative rarity ordering; not a specific price judgment.
Sources GIA Fancy Color Diamond Description
The colours exhibited by natural fancy colour diamonds are usually not very intense (often muted rather than pure and strong).
Evidence grade AScope: Describes a general trend of colour intensity in natural fancy colours; not a judgment of an individual stone.
Sources GIA Fancy Color Diamond Description
Fancy colour diamonds do not use the D-to-Z scale of colourless stones; they are described instead through saturation, tone and hue, with GIA applying a set of terms running from the weakest colour to the strongest (Faint through Fancy Deep and beyond). Colour is the dominant quality factor for such stones.
Evidence grade AScope: This describes the diamond quality factors the market generally prizes; it is not a grade for any specific specimen and is neither price nor investment advice; the 4Cs system applies to diamonds and is not transferable to coloured stones; a specimen's grades must be issued by an accredited laboratory.
Sources GIA Fancy Color Diamond Quality Factors · G&G Winter 1994
The GIA sources cited for this entry record no size superlative for fancy-colour diamond. The 1988 article's faceted-diamond superlative -- Cullinan I, 530.20 ct -- concerns a colourless stone, not a fancy-colour one, and no coloured-diamond size record appears in it.
Evidence grade AScope: States that the sources give no fancy-colour diamond record and that the 1988 article's faceted-diamond superlative is colourless. Records change over time; the statement is limited to the source year (1988).
Sources G&G Spring 1988
Limits of this research
- Research status: Only partial material-specific findings found; gaps are stated as gaps
- The cited source gives no general colour-cause mechanism; colour origin requires stone-by-stone laboratory determination and is not asserted here.
- The source states no absolute geological timescale for the formation of fancy colour diamonds (or of their colour).
- The source notes a qualitative trend that value rises with colour strength, but no specific price or investment judgment is made here.
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
- Fancy color diamond (state the colour origin)
GB/T 16553—2017 §5.1.1.3 · IMA Mineral List 2026-07 “Diamond”
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
Fancy Color Diamond's material identity has open questions that are not fully settled; this site lists it as "Fancy color diamond (state the colour origin)" pending further verification.
Evidence
- GB/T · §5.1.1.3
What this means for you
Before buying, check the recommended listing name "Fancy color diamond (state the colour origin)" 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
- 2026-09-26
Care and wear
No care facts are recorded for this entry itself. Its parent material has care records: see Diamond.
Treatments and identification leads
Registered treatmentsThe treatment registered for Fancy Color Diamond is irradiation. Values not givenIrradiation has status treated; for stability and market prevalence, the cited source gives no value, which is not the same as "none". Identification cluesThe identification lead is: when the sample is immersed in oil and examined under the microscope, the colour is concentrated in the surface layer and becomes gradually lighter from the outside inwards; a conclusion usually also requires combining infrared, near-infrared, UV-visible and photoluminescence spectral data. This lead applies to irradiated Fancy Color Diamond, and the cited GB/T 16553—2017 can only be used as a reference and does not govern this entry directly.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| irradiationStatus: treated | — | — | — | — | See identification leads |
Where each treatment acts (schematics): Irradiated
“—” means the cited source gives no value for that item, not “none”. Source: GB/T 16553—2017
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 Fancy Color Diamond, the name register records "Fancy Colour Diamond", for which no restriction on use as a name is recorded.
Chinese standard nameThe Chinese standard naming counterpart for Fancy Color Diamond is diamond (GB/T 16552—2017 Table A.1), and the name Fancy Color Diamond is not listed in the original. Names in four languagesFour-language names are given in Simplified Chinese, Traditional Chinese, English (Fancy Color Diamond) and Japanese (pending verification). Trade and mineralogical namesThe mineralogical name is diamond of the fancy-colour series, with the colour origin to be stated; the trade name/synonym is Fancy Colour Diamond. Recommended listing nameSuggested listing name: Fancy Color Diamond (state colour origin). Institution usageOn authority wording, GIA records Fancy Color Diamond (GIA Gem Encyclopedia); the FTC and CIBJO texts on file have no wording for Fancy Color Diamond (checked); Gem-A is unchecked; bodies without a recorded wording show the entry's own English name, which does not represent their position. Japanese namesThe entry has its own Japanese name, and the wording of Japan's GSJ for this name is not yet verified 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 (1) | ||||
| Fancy Colour DiamondEnglish | synonym | matched automatically | no restriction recorded | editorial ruling (no clause cited) |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- ファンシーカラー・ダイヤモンド（待核） (not yet checked for this body — the entry's own Japanese name is shown)
- GB/T naming counterpart (this name is not in the standard)
- 钻石 (GB/T 16552—2017 Table A.1)
- Mineralogical name
- Diamond of the fancy-colour series (colour origin to be stated)
- Trade names and synonyms
- Fancy Colour Diamond (synonym)
Four-language names
- 简体中文
- 彩色钻石
- 繁體中文
- 彩色鑽石
- English
- Fancy Color Diamond
- 日本語
- ファンシーカラー・ダイヤモンド（待核）
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural inorganic gem materials
- Browsing family
- Native-element minerals
- Identity tier
- Mineral / gemstone variety
- Mineral chemical class
- Native elements
- Construction or treatment status
- Natural identity; treatment status unknown
What it is and how it's identified
The material facts for Fancy Color Diamond are registered from GB/T 16553—2017, and each value is written by the cited clauses for diamond (the whole mineral species), not measured on Fancy Color Diamond separately. Chemical composition, fluorescence, UV-visible spectrum, infrared spectrum, Raman spectrum and magnification are likewise given for diamond (the whole mineral species) and are not repeated on the Fancy Color Diamond page; see the material facts of the Diamond entry. For diamond (the whole mineral species), Fancy Color Diamond has a Mohs hardness of 10 and a density of 3.51–3.53 g/cm³; as noted by this site, the density limits are derived from the cited clause value of 3.52 with a tolerance of ±0.01. Likewise for diamond (the whole mineral species), the refractive index of Fancy Color Diamond is 2.417, its dispersion 0.044, and it has no birefringence. In the untreated state, the body colour is yellow, brown, grey, and light to dark blue, green, orange, pink, red, purplish red, black and other colours; this site's note on colour is that the listed colours describe the colour itself and do not indicate whether it is natural or produced by treatment.
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, Raman spectrum, magnification: these whole-class features are given in the cited clause for diamond (the whole mineral species), so they are not repeated on the Fancy Color Diamond page; see the material facts on the Diamond entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of Fancy Color Diamond (how to read class-level values).
Durability
Fancy Color Diamond — Mohs hardness: 10
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
- diamond (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.1 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Physical properties
Fancy Color Diamond — density: 3.51–3.53 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- diamond (the whole mineral species)
- Qualification
The clause we cite gives 3.52, with a stated tolerance of ±0.01. The range shown here is worked out from that.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.1 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Optical
Fancy Color Diamond — refractive index: 2.417
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- diamond (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.1 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Fancy Color Diamond — birefringence: none
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- diamond (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.1 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Fancy Color Diamond — dispersion: 0.044
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- diamond (the whole mineral species)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.1 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Fancy Color Diamond — body colour: yellow, brown, grey, and light to dark blue, green, orange, pink, red, purplish red, black and other colours.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- Qualification
These are the colours the clause we cite lists for the fancy colour series of diamond. They describe the colour only, not whether it is natural or produced by treatment.
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.1 (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): 2.417 / 3.52; Closest values: 1Sphalerite 2.369 / 4, 2Synthetic Moissanite 2.67 / 3.22, 3Artificial Strontium Titanate 2.409 / 5.13, 4Rutile 2.753 / 4.23, 5Synthetic Rutile 2.76 / 4.26
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
Irradiation of Fancy Color Diamond can be identified: where the treatment state is treated, examination under the microscope with immersion shows colour concentrated in the surface layer and fading inward, and a conclusion usually needs infrared, near-infrared, UV-visible and photoluminescence spectral data together. The lead concerns irradiation, and GB/T 16553—2017 can be followed for Fancy Color Diamond as a reference only and does not govern it directly.
How far testing can go
Fancy Color Diamond that has undergone irradiation can be identified by the following features: Under the microscope with immersion, colour is concentrated at the surface and fades inward; a conclusion usually needs infrared, near-infrared, UV-visible and photoluminescence data together.
GB/T 16553—2017
- Treatment state
- treated
- Does this standard apply
- can be followed as a reference only
- Treatment
- irradiation
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.1.1 (irradiation) (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.
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.
- AQSIQ / SAC (China). GB/T 16553—2017 Gems — Testing.
- SAMR / SAC (China). GB/T 16552—2017 Gems — Nomenclature.
- RRUFF Project, in partnership with the IMA – International Mineralogical Association. IMA Mineral List.
- GIA – Gemological Institute of America (United States). Gem Encyclopedia.
- eCFR (United States). 16 CFR Part 23 — Guides for the Jewelry, Precious Metals, and Pewter Industries.
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.
Related-entry tree for Diamond on this site: 4 entries listed by this site's parent-entry links; synthetic, treated and similar entries carry their recorded state after the name; this page (Fancy Color Diamond) is marked.
- Diamond
Sub-entries (3)
- Black Diamond (treated)
- Fancy Color Diamond
- Synthetic Diamond (Synthetic product)
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| Page | Content | Status |
|---|---|---|
| Browsing family | Native-element minerals | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the Fancy Color Diamond 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. The entry exists so that buyers and sellers can check naming, disclosure and material facts item by item.