On this page
UnderstandWhat it is, what people ask, how far this page goes
Natural organic and biogenic materials · Organic or biogenic material · Natural identity; treatment status unknown
White Coral
Also known asBianco · Pure White · Shiro
The white variety of Precious Coral. It may be bleached or impregnated, and natural color and treatment must each be disclosed based on evidence. 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 White Coral forms and what gives its colourFormation setting, process and timescale, each finding graded and sourced
- How to identify White CoralIdentification points from the research literature; how far lab testing can go
- Treatments and enhancements of White Coral1 registered treatments: status, stability, how common they are and identification leads
- Caring for and wearing White CoralCleaning, heat, chemicals and light, as the cited sources give them
- Hardness, density and refractive index of White CoralEach value with its source and check date
- White Coral 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?
- Listing and disclosing White CoralThe listing name to use; what must be disclosed before sale
- Standard clauses that define White CoralWhich 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
White coral is the white variety of precious coral (family Corallidae). Under CIBJO's Coral Book, 'Pure White' (commercial name, i.e. Shiro) refers to Pleurocorallium konojoi: found in the South China Sea near Vietnam at depths of 80-300 m, uniform white, fan-shaped, average height 10-40 cm, trunk diameter 10-30 mm and weight 100-700 g. As a precious coral, white coral forms a branched skeleton of biomineralised calcium carbonate secreted by deep-water polyps; being a Corallidae coral used in jewellery, its trade status follows that of precious coral (this group is listed in CITES Appendix III at China's request).
Scope: Applies to an overview of the definition, occurrence and composition of white coral as the white variety of precious coral (corresponding to Pleurocorallium konojoi).
Sources CIBJO Coral Blue Book 2024 · CITES Checklist
Where it forms
In the South China Sea near Vietnam, at depths from 80 to 300 m.
Sources CIBJO Coral Blue Book 2024
Deep-water, low-light rocky sea bed (the shared setting of precious corals).
Sources CIBJO Coral Blue Book 2024
How it forms, step by step
Polyps of Pleurocorallium konojoi live colonially in deep water.
Sources CIBJO Coral Blue Book 2024
The polyps secrete biomineralised calcium carbonate, forming the fan-shaped hard skeleton.
Sources CIBJO Coral Blue Book 2024
The skeleton is uniform white, constituting the 'Pure White / Shiro' variety.
Sources CIBJO Coral Blue Book 2024
As a precious coral, it is managed in trade under the rules for the Corallidae group.
Sources CIBJO Coral Blue Book 2024 · CITES Checklist
Link to appearance
'Pure White' is uniform white and fan-shaped, with a porcelain-like lustre after polishing ('Shiro' means white).
Sources CIBJO Coral Blue Book 2024
Timescale
No authoritative growth-rate figure was available, so no timescale is stated.
Sources CIBJO Coral Blue Book 2024
Related base materials
- Precious coral: Collective name to which white coral belongs
- Pleurocorallium konojoi: Species corresponding to the trade name white coral (Pure White / Shiro)
Supporting findings
White coral (Pleurocorallium konojoi) is found in the South China Sea near Vietnam at depths of 80-300 m; it is uniform white and fan-shaped, with average height 10-40 cm, trunk diameter 10-30 mm and weight 100-700 g.
Evidence grade AScope: States the variety's locality and dimensions; general ranges.
Sources CIBJO Coral Blue Book 2024
White coral is a deep-water colonial coral whose polyps secrete a biomineralised calcium carbonate hard skeleton.
Evidence grade AScope: Describes its biological origin; no specific chemical values.
Sources CIBJO Coral Blue Book 2024
Recorded localities
This is an organic material; its localities are the harvest or culture areas (waters or species ranges) recorded by authoritative sources.
Seas and coasts
- South China Sea near VietnamRefers to the trade name Pure White/Shiro (P. konojoi), 80–300 m deep.
Sources CIBJO Coral Blue Book 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.
How it is identified
White coral can closely resemble bleached or otherwise pale corals, bone materials, and plastic imitations, so unaided inspection cannot reliably determine whether it is natural or treated. Confirming its identity is a laboratory task using microscopic structure and spectroscopic instruments; the nomenclature sources cited here give no self-test criteria, and the final conclusion must come from an accredited laboratory.
Evidence grade AScope: Appearance cannot replace identification; a qualified laboratory test is required, and this entry gives no self-test threshold.
Sources CIBJO Coral Blue Book 2024
Other research findings
White coral is the white variety of precious coral; in CIBJO's Coral Book, 'Pure White' (i.e. Shiro) refers to Pleurocorallium konojoi.
Evidence grade AScope: Defines the commercial name and its species; not a separate species.
Sources CIBJO Coral Blue Book 2024
CITES does not list the whole coral family Coralliidae: only four species — Corallium japonicum, Pleurocorallium elatius, P. konojoi and P. secundum — are in Appendix III at China's request (effective 01/07/2008). Whether a white coral is covered depends on which species it is.
Evidence grade AScope: Defines the trade-control level; no judgement on source legality.
Sources CIBJO Coral Blue Book 2024 · CITES Checklist
Limits of this research
- Research status: Formation, occurrence or other material-specific findings found in authoritative sources
- White coral is a white commercial variety of precious coral, not a separate species; its boundary is the CIBJO name (Pure White/Shiro).
- Note the level is CITES Appendix III (at China's request).
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
- White Coral (state the genus, species and any treatments)
GB/T 16552—2017 Table A.3 “Coral” · CIBJO Coral Blue Book 2024 §5.78, §5.28, Annex C §7.6
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Impregnated, Bleached, Filled / Fracture-filled (via parent material), Coated (via parent material), Dyed (via parent material)
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
White Coral is often subjected to impregnation. Under GB/T 16552-2017, impregnation is graded by the material used, and must be stated in the name wherever it counts as a treatment (§5.4.1, Table 1). Do not assume it is unenhanced.
Evidence
- CIBJO · 5.78
What this means for you
Before buying, check the recommended listing name "White Coral (state the genus, species and any treatments)" 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
- Disclosure rules for the treatments above can change as authorities update their standards; re-check before relying on this page.
- Last reviewed
- 2026-09-01
Trade-name ruling
- Laboratory identification required before the name is used.
- Suggested listing name
- White Coral (state the genus, species and any treatments)
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 normal care that applies to all corals, and so to White Coral (CIBJO Coral Book §6.1), and the special care the source gives for some corals without saying which ones (§6.2), are set out in full under care on the Coral entry.
Care
White Coral — care (cleaning): Some stones are susceptible to damage from ultrasonic cleaning. Do not expose them to ultrasonic cleaning.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code j
- Treatment state
- any treatment state
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, White Coral, p.40; §6.2 j (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
White Coral — care (chemicals): Treatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code k
- Treatment state
- treated
- Only after these treatments
- impregnation
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Official Gemstone Book (Coloured Stone Commission 2022) (CIBJO): §8 Annex C, White Coral, p.40; §6.2 k (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
White Coral — care (chemicals): porous, so do not let it come into contact with coloured fluids; particularly susceptible to attack by acids, so keep it away from acids.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code c, special-care code h
- 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, White Coral, p.40; §6.2 c, h (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
White Coral — care (wear): Some stones are prone to scratching due to low hardness. Wear them with care.
CIBJO Gemstone Book 2022
CIBJO Gemstone Book §6.2:special-care code a
- 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, White Coral, p.40; §6.2 a (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
White Coral — care (special care): assembled with polymers and dyed: special care (SC); avoid chemicals and solvents.
AGTA Gemstone Information Manual, 17th ed.
- Treatment state
- treated
- Only after these treatments
- dyeing, impregnation
Source & check 2026-09-26
- Source
- AGTA Gemstone Information Manual, 17th edition (August 2026) (AGTA): p.IX, Gemstone Information Chart, Coral White D,I, 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
CleaningOn cleaning White Coral, CIBJO (The World Jewellery Confederation) material states that, whatever the treatment state, it must not be cleaned ultrasonically. ChemicalsOn chemicals, CIBJO material states that White Coral is porous and, whatever the treatment state, should not come into contact with coloured liquids; it is particularly sensitive to acids and must be kept away from them. For treated White Coral that has been impregnated only, CIBJO material states that dyeing, oiling, resin impregnation, waxing or plastic impregnation are all not permanent, and it should be kept away from all solvents (including detergents), chemicals and heat. The 17th edition of the AGTA Gemstone Information Manual states that, for treated White Coral that has been dyed or impregnated only, White Coral assembled with polymer and dyed needs special care (marked SC) and should be kept away from chemicals and solvents. WearOn wear, CIBJO material states that White Coral is soft and scratches easily, so whatever the treatment state it should be worn with care.
This table scrolls sideways on narrow screens.
| Question | Matching entries |
|---|---|
| Can it go in an ultrasonic or steam cleaner? | care (cleaning) |
| Contact with acids, alkalis and household chemicals | Treatments with dye, oil, resin, wax or plastic are not permanent; keep it away from all solvents (including dish-washing liquids), chemicals and heat; porous, so do not let it come into contact with coloured fluids; particularly susceptible to attack by acids, so keep it away from acids |
| Wearing limits (knocks, settings) | care (wear) |
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 (cleaning) §6.2 j
- porous, so do not let it come into contact with coloured fluids; particularly susceptible to attack by acids, so keep it away from acids §6.2 c, h
- care (wear) §6.2 a
treated (Only after these treatments: impregnation)
treated (Only after these treatments: dyeing, impregnation)
Treatments and identification leads
Registered treatmentsThe treatment registered for White Coral is impregnation, with the status treated, stability unstable and prevalence common. Values not givenThe identification leads and source for impregnation are both recorded as “—”, meaning the cited source gives no value, not “none”.
This table scrolls sideways on narrow screens.
| Treatment | Market frequency (CIBJO) | Stability (CIBJO) | GB/T 16552 category | JJA/AGL listing | Identification leads |
|---|---|---|---|---|---|
| impregnationStatus: treated | commonly | unstable | — | — | — |
| Bleaching | — | — | Optimization | — | — |
| Filling | — | — | Graded — see §5.4.1, Table 1 | — | — |
| Coating | — | — | Graded — see §5.4.1, Table 1 | — | — |
| Dyeing | — | — | Treatment | — | — |
| bleaching | — | — | — | bleaching | — |
Where each treatment acts (schematics): Impregnated
“—” means the cited source gives no value for that item, not “none”. Source: CIBJO Gemstone Book 2022; GB/T 16552—2017 Table B.1 (row for Coral); 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 White Coral, the name register records "Bianco", "Pure White" and "Shiro", for which no restriction on use as a name is recorded (CIBJO Coral Blue Book 2024 Annex C 7.7 “Bianco”; CIBJO Coral Blue Book 2024 Annex C 7.7 “Pure White”; CIBJO Coral Blue Book 2024 Annex C 7.7 “Shiro”).
Standard and listing namesThe suggested listing name for White Coral is White Coral (state genus/species and treatment). The Chinese standard naming counterpart is coral (GB/T 16552—2017 Table A.3), and White Coral is not listed in the original GB/T 16552—2017; the mineralogical name is White precious coral (CIBJO Annex C). Trade and mineralogical namesMarket names include Bianco, Pure White and Shiro, based on CIBJO Coral Blue Book 2024 Annex C 7.7. Names in four languagesFour-language names are given in Simplified Chinese, Traditional Chinese, English (White Coral) and Japanese; the entry has its own Japanese name, and the wording of Japan's GSJ for White Coral is not yet verified by this site. Institution usageOn authority wording, GIA, CIBJO and Gem-A are unchecked, and the FTC text on file has no wording for this name (checked); bodies without a recorded wording show the entry's own English name, which does not represent their position.
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) | ||||
| BiancoEnglish | market name | matched automatically | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Bianco” |
| Pure WhiteEnglish | market name | matched automatically | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Pure White” |
| ShiroEnglish | market name | matched automatically | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Shiro” |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- 白珊瑚 (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)
- 珊瑚 (GB/T 16552—2017 Table A.3)
- Mineralogical name
- White precious coral (CIBJO Annex C)
- Trade names and synonyms
- Bianco (market name) · Pure White (market name) · Shiro (market name)
Four-language names
- 简体中文
- 白珊瑚
- 繁體中文
- 白珊瑚
- English
- White Coral
- 日本語
- 白珊瑚
See also: Misleading and prohibited trade names · Supplementary name index
Classification
- Origin
- Natural materials
- Material domain
- Natural organic and biogenic materials
- Browsing family
- Coral materials
- Identity tier
- Organic or biogenic material
- Mineral chemical class
- Not applicable
- Construction or treatment status
- Natural identity; treatment status unknown
Treatments listed by standards
GB/T Table B.1For White Coral, this site applies the "Coral" row of GB/T 16552—2017 Annex B, Table B.1: bleaching is an optimization; filling and coating are both marked as graded; dyeing is a treatment. What Table B.1 is, and how the grades are defined, are on the Gem treatments page. JJA/AGL designationsIn the "principal gem names" table of the Japanese JJA/AGL Definitions and Nomenclature of Gems and Ornamental Materials, November 2025 revision, Coral is listed under species coral and colour white, with decolourisation (bleaching) listed; a note states that the listing is under Coral and that the original does not name White Coral specifically.
GB/T 16552-2017, Annex B, Table B.1
Under the “Coral” row of Table B.1: Bleaching Optimization; Filling Graded — see §5.4.1, Table 1; Coating Graded — see §5.4.1, Table 1; Dyeing Treatment. The full row, with the effect column, is on the Coral 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 |
|---|---|---|---|---|
| Coral | Coral | white | bleaching (Bleached) | listed under “Coral” in the table; this page is related (the source does not name it) |
JJA/AGL definitions and nomenclature (2025 revision), table of principal gem names, p.13
How to read the JJA/AGL table: see the Gem treatments page.
What it is and how it's identified
Among the registered material facts for White Coral, the items marked with a class range take values for that class; they are not measurements of White Coral itself. For calcareous coral: Mohs hardness 3–4.5; untreated, it effervesces with a drop of hydrochloric acid; density 2.6–2.7 g/cm³, derived from the clause value of 2.65 and a tolerance of ±0.05; refractive index 1.48–1.66, a common spot-method reading rather than an absolute limit. For coral as a whole (calcareous and horny): structurally, calcareous coral is a cryptocrystalline aggregate in its inorganic part and amorphous in its organic part, while horny coral is amorphous; cleavage usually not seen in an aggregate; optic character aggregate; untreated, pleochroism not measurable for an aggregate, and lustre waxy, vitreous on polished surfaces.
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 calcareous coral, coral as a whole (calcareous and horny), so they are not repeated on the White Coral page; see the material facts on the Coral entry.
Items below that name the class they cover give the cited clause’s value for that whole class, not a measurement of White Coral (how to read class-level values).
Structure
White Coral — structure (overall): calcareous coral: the inorganic part is a cryptocrystalline aggregate and the organic part is non-crystalline. Horny coral: non-crystalline.
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- coral as a whole (calcareous and horny)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
Durability
White Coral — Mohs hardness: 3–4.5
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
- What this covers
- calcareous coral
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
White Coral — cleavage: generally not seen on an aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- coral as a whole (calcareous and horny)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
White Coral — stability: effervesces on contact with hydrochloric acid
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- calcareous coral
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
For White Coral, the stability of impregnation is “unstable”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- impregnation
- Qualification
This says how well the treatment holds up, not how durable White Coral itself is.
- General note
- no durability verdict here
Source & check 2026-09-25
- Source
- Fact checked on
- 2026-09-25
Physical properties
White Coral — density: 2.6–2.7 g/cm³
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- calcareous coral
- Qualification
The clause we cite gives 2.65, with a stated tolerance of ±0.05. The range shown here is worked out from that.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
Optical
White Coral — optic character: aggregate
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- coral as a whole (calcareous and horny)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
White Coral — refractive index: 1.48–1.66
GB/T 16553—2017
- Does this standard apply
- applies to this entry
- What this covers
- calcareous coral
- Qualification
The clause we cite gives this as a value commonly read by the spot (distant-vision) method. It is a common value, not an absolute limit.
Source & check 2026-09-21
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (locator checked 2026-09-21)
- Fact checked on
- 2026-09-21
White Coral — pleochroism: not measurable on an aggregate
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- coral as a whole (calcareous and horny)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (locator checked 2026-09-26)
- Fact checked on
- 2026-09-26
White Coral — fluorescence (overall): none to strong, blue-white
GB/T 16553—2017
UV fluorescenceblue-whitenone–strongDots are illustrative colours built from the colour names, not measured values
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 Fluorescence (locator checked 2026-09-28)
- Fact checked on
- 2026-09-26
Quality factors
White Coral — quality factor (lustre): waxy; polished surfaces take a vitreous lustre.
GB/T 16553—2017
- Treatment state
- untreated
- Does this standard apply
- applies to this entry
- What this covers
- coral as a whole (calcareous and horny)
Source & check 2026-09-26
- Source
- GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (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): 1.57 / 2.65; Closest values: 1Scapolite 1.558 / 2.67, 2Changhua Stone 1.56 / 2.6, 3Amethyst 1.548 / 2.67, 4Balin Stone 1.56 / 2.55, 5Qingtian Stone 1.565 / 2.77
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 CIBJO laboratory protocol covers White Coral under “Coral” (§6.2.4): see identification on the Coral entry; the required tests are listed on the CIBJO laboratory protocol table for Coral.
How far testing can go
For White Coral in trade, the reported frequency of impregnation is “commonly”.
CIBJO Gemstone Book 2022
- Treatment state
- treated
- Treatment
- impregnation
Source & check 2026-09-25
- Source
- Fact checked on
- 2026-09-25
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Clause-level definitions
The term registered for White Coral in the clause-level definitions is White Coral, based on GB/T 16552—2017 Annex A. The definition points to the original: the full description is in Appendix C of the CIBJO Coral Blue Book 2024, and see also the name coral in GB/T 16552—2017 Annex A. The cross-check result is that it is listed directly in GB/T, and no identically titled standalone entry was found in CIBJO.
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| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| White Coral | GB/T 16552-2017 Annex A | For the full description, see Annex C §7.6 in CIBJO Coral Blue Book 2024; Table A.3 “Coral” in GB/T 16552—2017. | 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.
- CITES Secretariat. Appendices I, II and III, valid from 5 March 2026.
- CIBJO – The World Jewellery Confederation. The Coral Book (Blue Book), 2024.
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 Coral on this site: 12 entries listed by this site's parent-entry links; synthetic, treated and similar entries carry their recorded state after the name; this page (White Coral) is marked.
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Coral materials | Live |
| Treatments recorded for this material | Impregnated, Bleached, Filled / Fracture-filled (via parent material), Coated (via parent material), Dyed (via parent material) | Live |
| Related articles | To be added (placeholder) | Planned |
Who maintains this page
The material facts in the White Coral 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.