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Natural organic and biogenic materials · Organic or biogenic material · Natural identity; treatment status unknown

Black Coral

Also known asaccarbaar · akabar · horn coral · king coral (conditional name)

Coral material from the order Antipatharia, the whole order being listed in CITES Appendix II; a golden appearance produced by bleaching must be disclosed. Also known as king coral. 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.

Edited by RalphReviewed by JuneLast updated 2026-10-12Who maintains this page

Care and wear

What this page can answer

This page covers

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

Black coral is the collective name for colonies of the order Antipatharia (subclass Hexacorallia) and is a coral that is non-calcareous and mostly organic. The colonies are flexible, spiny and tree-like, and their skeletons, very dark brown to black, are built of protein and chitin—fundamentally unlike precious coral, which is calcareous and mainly calcium carbonate, in both material and origin. Black coral is found in nearly all parts of the world, and especially where currents are strong, down to depths of 6000 m; the Caribbean, Hawaii and Oceania rank as notable sources; it can be bleached to give a golden colour ('golden coral'). The entire order Antipatharia, including the genus Antipathes, appears in CITES Appendix II.

Scope: Applies to an overview of the definition, composition, distribution and trade controls of black coral as members of the order Antipatharia (non-calcareous corals with an organic skeleton).

Sources CIBJO Coral Blue Book 2024 · CITES Checklist

Where it forms

Strong-current marine environments almost worldwide, at depths up to 6000 m; the Caribbean, Hawaii and Oceania are important sources.

Sources CIBJO Coral Blue Book 2024

Deep water (a setting different from shallow reef corals and precious corals).

Sources CIBJO Coral Blue Book 2024

How it forms, step by step

  1. Black coral polyps live colonially, forming flexible, spiny, tree-like or branched colonies.

    Sources CIBJO Coral Blue Book 2024

  2. The colony secretes a non-calcareous skeleton composed of protein and chitin.

    Sources CIBJO Coral Blue Book 2024

  3. The skeleton is very dark brown to black.

    Sources CIBJO Coral Blue Book 2024

  4. It may be bleached to obtain a golden colour, used as 'golden coral'.

    Sources CIBJO Coral Blue Book 2024

Link to appearance

Black coral is very dark brown to black, flexible and spiny, tree-like; lacking a calcareous skeleton it differs from the porcelain-like calcareous precious corals, and can be bleached to a golden colour.

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

  • Antipatharia (order): Taxonomic order to which black coral belongs; the name derives from this order

Supporting findings

Black coral is found in nearly all parts of the world, and especially where currents are strong, down to depths of 6000 m; the Caribbean, Hawaii and Oceania rank as notable sources.

Evidence grade A

Scope: States distribution and depth; not fisheries management.

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.

Locality sketch mapLand outlines only; the map does not depict any national or regional boundary. Dots mark approximate positions. Base map: Natural Earth (public domain).

Seas and coasts

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.

Human use and museum objects

The objects catalogued as coral (e.g. Cleveland Museum of Art, 1940.499; The Met, 43.164, 2009.300.2984a–c) are none identified as black coral (order Antipatharia); they attest to coral used for beads and inlays but do not evidence the use of black coral.

Evidence grade A

Scope: Evidence is generic 'coral', belonging to the broader coral record and not confirmable as black coral (Antipatharia); no inference about black coral use is made.

Sources Cleveland Museum of Art 1940.499 · The Met 2009.300.2984a–c

Museum objects catalogued as coral cluster after the 16th century and extend into the modern era, e.g. a Peruvian coral necklace before 1532 (Cleveland Museum of Art, 1940.499), a 1704 chasuble with accessories (The Met, 2009.300.2984a–c), a statue robe of ca. 1690–1720 (The Met, 43.164) and a Qing Mandarin necklace (Cleveland Museum of Art, 1952.472). These records mostly say only 'coral', usually meaning red/precious coral, and none is identified by the museum as black coral (order Antipatharia). They therefore show only that coral was used for beads and inlays, and cannot serve as evidence for the use of black coral. The parent material behind black coral is absent from this set of museum evidence, so no inference about the historical use of black coral is drawn here.

Sources Cleveland Museum of Art 1940.499 · The Met 2009.300.2984a–c

Scope: Museum objects attest only to the existence and date of the individual documented pieces; they do not evidence widespread ancient use of the material, nor the origin, naturalness or treatment of any modern specimen.

Objects cited

1500155016001650170017501800185019001950CMA 1940.499before 1532Met 43.164ca. 1690–1720CMA 1952.4721700sCMA 1916.2901700s–1800sMet 2009.300.2984a–c1704Met 55.111.5619th–first half 20th century
Dates of museum objectsDates from the museums' open-access records (CC0); each bar spans the whole period named in the record, with qualifiers such as “early” or “possibly” kept in the label rather than turned into a narrower range; an arrow marks a record that reads “before” or “after” a yearSource: The Met / Cleveland Museum of Art open-access records

How it is identified

Black coral resembles dyed horn and bone, plastic, and other dark imitations, and unaided inspection or simple handling cannot reliably establish its material identity. Confirmation is a laboratory task that generally uses microscopic structure and spectroscopic instruments; the cited sources offer no self-identification method, and conclusions must be issued by an accredited laboratory or qualified body.

Evidence grade A

Scope: Appearance cannot replace identification; testing by a qualified laboratory is required, and this entry provides no self-test method.

Sources CIBJO Coral Blue Book 2024

Other research findings

Black coral is the generic designation of colonies of the order Antipatharia (subclass Hexacorallia), a non-calcareous coral whose skeleton is composed of protein and chitin, fundamentally different from calcareous precious coral.

Evidence grade A

Scope: Defines black coral's taxonomy and material nature (non-calcareous organic); not a single species.

Sources CIBJO Coral Blue Book 2024

Black coral colonies are flexible, spiny, tree-like or branched, with very dark brown to black skeletons that may be bleached to a golden colour.

Evidence grade A

Scope: Describes morphology and colour; no quantitative chemistry.

Sources CIBJO Coral Blue Book 2024

The whole order Antipatharia (including the genus Antipathes) is listed in CITES Appendix II, so legality depends on species and permits.

Evidence grade A

Scope: Defines the trade-control level; no judgement on source legality.

Sources CIBJO Coral Blue Book 2024 · CITES Checklist

Black coral and precious coral belong to different groups: precious coral is limited to three Corallidae genera and is calcareous (mainly calcium carbonate); black coral belongs to the order Antipatharia and is non-calcareous and organic.

Evidence grade A

Scope: Defines the boundary between black coral and precious coral; no specific locality.

Sources CIBJO Coral Blue Book 2024

The CITES Appendices valid from 5 March 2026 list the whole order of black corals (Antipatharia spp.) in Appendix II. A listing covers the whole animal, live or dead, and its parts and derivatives fall in the same Appendix.

Evidence grade A

Scope: States only what is printed in the CITES Appendices valid from 5 March 2026 and their interpretation notes; it does not cover national law, exemptions or permits for any particular item. Not legal advice.

Sources CITES Appendices (2026)

Under the CITES Convention, Appendix II covers species that, although not necessarily now threatened with extinction, may become so unless trade in their specimens is subject to strict regulation; export of an Appendix II specimen requires the prior grant and presentation of an export permit.

Evidence grade A

Scope: Summarises the Convention text only. CITES governs international trade; each Party may adopt stricter domestic measures, and exemptions are not covered here. Not legal advice for any particular item.

Sources CITES Convention text

Limits of this research

  • Research status: Formation, occurrence or other material-specific findings found in authoritative sources
  • Black coral is a generic name derived from the order Antipatharia, not a separate species; materially different from calcareous precious coral.
  • Note the level is CITES Appendix II (the whole order), unlike the Appendix III of precious coral.

Methodology

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
Black Coral (only where lawful and the documentation is complete)

GB/T 16552—2017 Table A.3 “Coral” · CIBJO Coral Blue Book 2024 §5.12, §5.28

Construction or treatment status

Natural identity; treatment status unknown

Treatments recorded for this material: 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

"Black Coral" is a market name rather than a mineral species name; before using it, verify: Laboratory identification required before the name is used.

Evidence

  • CIBJO · 5.12

What this means for you

Before buying, check the recommended listing name "Black Coral (only where lawful and the documentation is complete)" and any disclosed treatments on this page, and ask the seller for a grading report if in doubt.

Known uncertainty

Last reviewed
2026-09-01

Trade-name ruling

  • Laboratory identification required before the name is used.
Suggested listing name
Black Coral (only where lawful and the documentation is complete)

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 Black 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

Black 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
Fact checked on
2026-09-25

Black Coral — care (chemicals): porous, so do not let it come into contact with coloured fluids; dissolves on contact with solvents such as nail varnish remover; keep it away from all solvents and other strong chemicals.

CIBJO Gemstone Book 2022

CIBJO Gemstone Book §6.2:special-care code c, special-care code i

Treatment state
any treatment state
Source & check 2026-09-25
Source
Fact checked on
2026-09-25

Black 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
Fact checked on
2026-09-25

Black 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
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

CleaningBlack Coral must not be cleaned ultrasonically; this conclusion, given by the Official Gemstone Book of CIBJO, the World Jewellery Confederation (Coloured Stone Commission 2022), applies regardless of treatment status. ChemicalsOn chemicals, the same CIBJO Gemstone Book states that black coral is porous and should not come into contact with coloured liquids, and that solvents such as nail-polish remover will dissolve it, so keep it away from all solvents and other strong chemicals; this conclusion likewise applies regardless of treatment status. WearOn wear, the CIBJO Gemstone Book states that black coral is soft and scratches easily, so wear it with care; this conclusion also applies regardless of treatment status. The 17th edition of the American Gem Trade Association (AGTA) Gemstone Information Manual states that black coral assembled with polymer and dyed needs special care (marked SC) and should be kept away from chemicals and solvents; this applies only to black coral whose status is treated and that has been dyed and impregnated.

This table scrolls sideways on narrow screens.

QuestionMatching entries
Can it go in an ultrasonic or steam cleaner?care (cleaning)
Contact with acids, alkalis and household chemicalsporous, so do not let it come into contact with coloured fluids; dissolves on contact with solvents such as nail varnish remover; keep it away from all solvents and other strong chemicals
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

treated (Only after these treatments: dyeing, impregnation)

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.

TreatmentMarket frequency (CIBJO)Stability (CIBJO)GB/T 16552 categoryJJA/AGL listingIdentification leads
Bleaching——Optimization——
Filling——Graded — see §5.4.1, Table 1——
Coating——Graded — see §5.4.1, Table 1——
Dyeing——Treatment——
bleached black coral———bleached black coral—

“—” means the cited source gives no value for that item, not “none”. Source: 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 Black Coral, the name register records "accarbaar", "akabar", "horn coral" and "king coral", for which no restriction on use as a name is recorded (CIBJO Coral Blue Book 2024 Annex C 7.9.2 “Black coral” “accarbaar / akabar / horn coral / king coral”; CIBJO Coral Blue Book 2024 Annex C 7.9.1 “Bamboo coral” “mountain coral / Chinese coral / sea bamboo coral / king coral / tiger coral / jointed coral”).

Standard and listing namesThe national-standard name corresponding to Black Coral is coral (GB/T 16552—2017 Table A.3); the name itself is not listed in the original text. The suggested listing name is Black Coral (only where legal and fully documented). Names in four languagesThe four-language names cover Simplified Chinese, Traditional Chinese, English (Black Coral) and Japanese. Institution usageOn authority wording, FTC and CIBJO have Black Coral on record, GIA and Gem-A are unchecked, and bodies without a record show the entry's own English name, which does not represent their position; the GSJ (Japan) wording for the entry's own Japanese name is not yet verified by this site. Qualifiers stripped from the title name: FTC notes Antipatharia spp. and CITES Appendix II, with the species to be disclosed; CIBJO notes Antipatharia, CITES Appendix II and the CIBJO Coral Book. National standard namesThe Germany (RAL) formal name is Schwarze Koralle and the European Union formal name is Black Coral, both noting the whole order ANTIPATHARIA, CITES Appendix II and EU Annex B (VO (EU) 2026/1383). Candidate search termsThe market names accarbaar, akabar and horn coral have no recorded usage restriction, and king coral is used only as a candidate search term; the basis is the Black coral trade names recorded in the CIBJO Coral Blue Book 2024, with king coral also listed in the same Blue Book as a trade alias of Bamboo coral.

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.

NameTypeMatchingUse as a nameBasis
no restriction recorded (4)
accarbaarEnglishmarket namematched automaticallyno restriction recordedCIBJO Coral Blue Book 2024 Annex C 7.9.2 “Black coral” “accarbaar / akabar / horn coral / king coral”
akabarEnglishmarket namematched automaticallyno restriction recordedCIBJO Coral Blue Book 2024 Annex C 7.9.2 “Black coral” “accarbaar / akabar / horn coral / king coral”
horn coralEnglishmarket namematched automaticallyno restriction recordedCIBJO Coral Blue Book 2024 Annex C 7.9.2 “Black coral” “accarbaar / akabar / horn coral / king coral”
king coralEnglishmarket namesearch candidate onlyno restriction recordedCIBJO Coral Blue Book 2024 Annex C 7.9.2 “Black coral” “accarbaar / akabar / horn coral / king coral”; CIBJO Coral Blue Book 2024 Annex C 7.9.1 “Bamboo coral” “mountain coral / Chinese coral / sea bamboo coral / king coral / tiger coral / jointed coral”

How each authority words this name: see Names › Authority wording.

Authority wording

GIA, FTC, CIBJO, Gem-A
Black Coral (on record for FTC, CIBJO; GIA, Gem-A unchecked — bodies without a recorded wording show the entry's own English name)
GSJ (Japan) formal name
黒珊瑚 (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
Black coral material from the order Antipatharia; the entire order is listed in CITES Appendix II
Trade names and synonyms
king coral (market name; conditional name) · accarbaar (market name) · akabar (market name) · horn coral (market name)

Four-language names

简体中文
黑珊瑚
繁體中文
黑珊瑚
English
Black Coral
日本語
黒珊瑚

National and regional formal names

Germany (RAL)
Schwarze Koralle (ANTIPATHARIA spp., gesamte Ordnung; CITES Anhang II und EU-Anhang B gemäß VO (EU) 2026/1383, in Kraft seit 29.06.2026)
European Union
Black Coral (ANTIPATHARIA spp., whole order; CITES Appendix II and EU Annex B per Reg. (EU) 2026/1383, in force 2026-06-29)

Qualifiers stripped from the headline name

  • FTC: (Antipatharia spp., CITES Appendix II; disclose species)
  • CIBJO: (Antipatharia; CITES Appendix II; CIBJO Coral Book)

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.1Black Coral is assigned the Coral row of GB/T 16552—2017 Annex B, Table B.1: bleaching is listed as an enhancement; filling and coating are covered by separate grade notes; dyeing is listed as a treatment. JJA/AGL designationsThe 2025 revised edition of the main gemstone nomenclature table of the JJA/AGL (Japan) lists Coral under the species name coral, in a brownish-yellow colour, and states that it is produced by decolorising black coral (bleaching); the original does not name Black 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 nameSpeciesColourListed in the tableNotes
CoralCoralbrownish yellowbleached black coral (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

Black Coral is a colonial antipatharian coral of the order Antipatharia, composed of protein and chitin; it is flexible and tough, spiny, grows in tree-like colonies, and its colour is very dark brown to black. It is often bleached to obtain a golden colour, and the entire order Antipatharia is listed in CITES Appendix II. Registered under coral as a whole (calcareous and horny): in calcareous coral the inorganic part is a cryptocrystalline aggregate and the organic part amorphous, horny coral is amorphous, and the optical character is aggregate; untreated, the lustre is waxy, vitreous on polished surfaces. Registered under horny coral, the Mohs hardness of 2–3 is the range for the whole class, not a measurement of Black Coral, and the CIBJO Coral Book states that black coral is non-calcareous; untreated, it does not react with hydrochloric acid; density 1.3–2.12 g/cm³, derived from the cited clause value of 1.35 and the permitted tolerances of +0.77 and −0.05; refractive index 1.55–1.58, where the cited clause gives the readings commonly obtained by the spot method, typical values rather than absolute limits, derived from 1.56–1.57 and the permitted tolerance of ±0.01.

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 coral as a whole (calcareous and horny), horny coral, so they are not repeated on the Black 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 Black Coral (how to read class-level values).

Definition

Black Coral: generic designation of the colonial common coral belonging to the order Antipatharia (subclass Hexacorallia). These form quite flexible, spiny, tree like, unbranched or branched colonies composed of protein and chitin (non-calcareous skeletons) with very dark brown to black colour.

CIBJO Coral Blue Book 2024

Qualification

Bleaching is commonly used to obtain a golden colour; all Antipatharia are listed in Appendix II of CITES.

Source & check 2026-09-22
Source
Fact checked on
2026-09-22

Structure

Black 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

Black Coral — Mohs hardness: 2–3

GB/T 16553—2017

123456789102–3References (diamond = value, bar = range; below)

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))

Mohs hardnessSource: GB/T 16553—2017
Does this standard apply
applies to this entry
What this covers
horny coral
Qualification

This is the range for the whole class, not a measured value for this variety. The value comes from the horny-coral branch of the cited clause; the CIBJO Coral Book describes this coral as non-calcareous.

Source & check 2026-09-20
Source
  • GB/T 16553—2017 Gems — Testing (GB/T): §5.3.4 (locator checked 2026-09-20)
Fact checked on
2026-09-20

Black 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

Black Coral — stability: Hydrochloric acid has no effect on it

GB/T 16553—2017

Treatment state
untreated
Does this standard apply
applies to this entry
What this covers
horny 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

Physical properties

Black Coral — density: 1.3–2.12 g/cm³

GB/T 16553—2017

0.51.52.53.54.55.56.57.51.3–2.12
Specific gravitySource: GB/T 16553—2017
Does this standard apply
applies to this entry
What this covers
horny coral
Qualification

The clause we cite gives 1.35, with a stated tolerance of +0.77 / -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

Black 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

Black Coral — refractive index: 1.55–1.58

GB/T 16553—2017

1.31.72.12.52.93.31.55–1.58
Refractive indexSource: GB/T 16553—2017
Does this standard apply
applies to this entry
What this covers
horny 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. The clause we cite gives 1.56–1.57, with a stated tolerance of ±0.01. 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

Black 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

Quality factors

Black 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.

1.541.561.581.41.61.82Refractive indexSpecific gravity12345Black Coral

This material (RI / SG midpoints): 1.565 / 1.71; Closest values: 1Mammoth Ivory 1.53 / 1.75, 2Ivory 1.535 / 1.85, 3Coral 1.57 / 2, 4Plastic 1.58 / 1.3, 5Turtle Shell 1.545 / 1.31

Show the full chart (330 registered materials)1.41.51.61.71.81.922.12.22.32.41234567Refractive indexSpecific gravity12345Black Coral

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

Refractive index × specific gravity (all registered materials)Each dot is one material's registered refractive index and specific gravity (range midpoints, not measurements); gold = this material, dark = the nearest few (picked on this site by distance in RI ÷ 0.02 and SG ÷ 0.1, leaving out near-identical varieties of the same species)Source: each material's registered refractive index and specific gravity facts (GB/T 16553 and others; sources on each entry)

Related CIBJO terms

Black coral

common coral of very dark brown to black colour, composed of protein and chitin, belonging to the order Antipatharia (subclass Hexacorallia) that are quite flexible, spiny, tree like, unbranched or branched. May be bleached to obtain golden coloration. Note — see Clause2 Normative References; Convention on International Trade in Endangered Species of Wild Fauna and Flora.

CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.12, p.11

Definitions are quoted verbatim from the cited CIBJO Blue Book; […] marks an excerpt, and the full definition is at the cited clause.

Testing and market

The CIBJO laboratory protocol covers Black 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

Each row's “Source & check” expands to the full source; the date beside it is the fact check date.

Clause-level definitions

In the clause-level definitions, Black Coral is recorded under the term Black Coral, against GB/T 16552-2017 Annex A; the definition is recorded as: for the full description, see ANTIPATHARIA in CITES Appendices 2026, with Table A.3 “Coral” in GB/T 16552—2017 noted. Cross-check result: listed directly by GB/T; CIBJO carries no standalone entry under the same name.

This table scrolls sideways on narrow screens.

TermClauseDefinitionCross-check
Black CoralGB/T 16552-2017 Annex AFor the full description, see ANTIPATHARIA in CITES Appendices 2026; 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

GB/T 16552—2017
Not listed the name does not occur anywhere in the text; scope: Chapter 1 “Scope” · Source
GB/T 16552—2017
Listed Table A.3 “Coral” · Source
CIBJO Coral Blue Book 2024
Listed §5.12 · Source
CIBJO Coral Blue Book 2024
Listed §5.28 · Source
CITES Appendices 2026
Listed “ANTIPATHARIA” · Source
CITES Convention text
Naming rule Article IV(2) · Source

Sources

Further reading

Related pages

Treatments recorded for this material

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 (Black Coral) is marked.

This table scrolls sideways on narrow screens.

PageContentStatus
Browsing familyCoral materialsLive
Treatments recorded for this materialBleached, Filled / Fracture-filled (via parent material), Coated (via parent material), Dyed (via parent material)Live
Related articlesTo be added (placeholder)Planned

Who maintains this page

The material facts in the Black 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.

Facts editor
Ralph
Reviewer
June
How facts are checked
Each fact is matched to the clause it cites; facts checked between 2026-09-20 and 2026-09-26
Last revised
2026-10-12
Purpose
Lets buyers and sellers check naming, disclosure and material facts clause by clause.

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