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
Precious Coral
Also known asAka Coral (conditional name) · Cerasuolo · Deep Sea (conditional name) · Garnet coral · Miss (conditional name) · Missu · Misu · Momo · Momo Coral (conditional name) · Sardinia Coral (conditional name) · Satsuma (conditional name) · Shinkai
Red, pink and white corals limited to the three genera Corallium, Pleurocorallium and Hemicorallium; the term cannot be used for all corals, and species and source must be documented. Also known as Cerasuolo, Momo. 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 Precious Coral 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 Precious CoralIdentification points from the research literature; how far lab testing can go and whether a synthetic exists
- Treatments and enhancements of Precious CoralThe enhancements and treatments the GB/T and JJA/AGL tables list
- Caring for and wearing Precious CoralCleaning, heat, chemicals and light, as the cited sources give them
- Hardness, density and refractive index of Precious CoralEach value with its source and check date
- Precious Coral in English, Chinese and Japanese; national standard namesNames in four languages, the GB/T standard name and the suggested listing name, names in national standards; and: Which of GIA, FTC, CIBJO and Gem-A have a name for it on record, and do those agree?
- Name origin and history of Precious CoralHow people have used it, with museum objects
- Listing and disclosing Precious CoralThe listing name to use; what must be disclosed before sale
- Standard clauses that define Precious 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
Precious coral is the jewellery-industry designation for certain species of the family Corallidae, limited to the three genera Corallium, Pleurocorallium and Hemicorallium; they include red, pink, orange and white varieties with a porcelain-like lustre after polishing, with specific gravity about 2.8 and Mohs hardness 3. They are colonial marine corals whose polyps in deep water secrete a biomineralised calcium carbonate hard skeleton (about 82-87% calcium carbonate with minor magnesium); the red colour comes from carotenoid pigments. Precious corals are generally collected below 50 m and live in ecosystems entirely different from shallow-water reef corals.
Scope: Applies to an overview of the definition, biogenic origin and composition of precious coral as a collective name for three genera of the family Coralliidae; for specific varieties (red / white / pink coral), see their respective entries.
Sources CIBJO Coral Blue Book 2024 · GIA Reading List: Mediterranean Coral · CITES Checklist
Where it forms
Warm, clean water on rocky sea beds with low light levels, generally below 50 m and down to about 300 m.
Sources CIBJO Coral Blue Book 2024 · GIA Reading List: Mediterranean Coral
The Mediterranean and adjacent Atlantic (Corallium rubrum) and the central-western Pacific (other red coral species).
Sources CIBJO Coral Blue Book 2024
How it forms, step by step
Precious coral polyps live colonially in deep, low-light water and secrete biomineralised calcium carbonate.
Sources CIBJO Coral Blue Book 2024
The calcium carbonate forms intermeshed spicules and a hard skeletal branch usable as gem material.
Sources CIBJO Coral Blue Book 2024
In living specimens the skeleton is red, owing to carotenoid pigments.
Sources GIA Reading List: Mediterranean Coral
Different genera/species grow at characteristic depths in their respective seas, yielding red, pink and white varieties.
Sources CIBJO Coral Blue Book 2024
Link to appearance
Polished precious coral has a porcelain-like lustre, ranging from bright red and dark red (with a lengthwise white 'soul') to pink, orange and pure white; the red is due to carotenoid pigments.
Sources GIA Reading List: Mediterranean Coral
Timescale
No authoritative growth-rate figure was available, so no timescale is stated.
Sources CIBJO Coral Blue Book 2024
Related base materials
- Corallium: Genus to which precious coral belongs
- Pleurocorallium: Genus to which precious coral belongs
- Hemicorallium: Genus to which precious coral belongs
Supporting findings
Precious coral is a colonial coral of the deep ocean that builds a hard skeleton by secreting biomineralised calcium carbonate. Its chemical make-up is calcium carbonate (82–87%), together with a minor amount of magnesium.
Evidence grade AScope: Describes the biomineralisation and composition of precious coral; no specific locality.
Sources CIBJO Coral Blue Book 2024
Precious corals are generally collected below 50 m and live in ecosystems entirely different from shallow-water reef corals.
Evidence grade AScope: States collection depth and ecological distinction; 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.
Seas and coasts
- Mediterranean SeaMediterranean coral is found mostly in the Mediterranean Sea.
Sources CIBJO Coral Blue Book 2024
- Atlantic Ocean (off northern Africa, Spain and Portugal)
Sources CIBJO Coral Blue Book 2024
- South China Sea
Sources CIBJO Coral Blue Book 2024
- Sea of Japan
Sources CIBJO Coral Blue Book 2024
- Pacific Ocean
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.
Causes of colour and optical effects
The red coral skeleton is composed of intermeshed calcium carbonate spicules, and the red colour is due to carotenoid pigments; red corals grow in warm clean waters on rocky sea beds with low light levels, typically 10-300 m deep.
Evidence grade AScope: Applies to red coral (Corallium rubrum) colour cause and habitat; depths vary slightly by species.
Sources GIA Reading List: Mediterranean Coral
Human use and museum objects
Coral beads and inlaid objects in museum holdings date after the 16th century and continue into the modern era, e.g. a Peruvian coral necklace before 1532 (Cleveland Museum of Art, 1940.499) and a Qing Mandarin necklace (Cleveland Museum of Art, 1952.472); the records say only 'coral' without identifying precious-coral species.
Evidence grade AScope: Evidence belongs to the parent material behind precious coral; records do not resolve species and make no exclusive claim for the name.
Sources Cleveland Museum of Art 1940.499 · The Met 2009.300.2984a–c
Museum objects identified as coral cluster after the 16th century and extend into the modern era. Earlier pieces include a Peruvian coral necklace before 1532 (Cleveland Museum of Art, 1940.499), a 1704 chasuble with accessories (The Met, 2009.300.2984a–c) and a statue robe of ca. 1690–1720 (The Met, 43.164); the rest are largely 18th–20th century works such as a Qing Mandarin necklace (Cleveland Museum of Art, 1952.472), an Algerian silver-set coral necklace (The Met, 55.111.56) and a Nepalese nose ring (Cleveland Museum of Art, 1916.290). Museum records mostly say only 'coral', without separating precious coral (genera Corallium etc.) from other corals, so this evidence belongs to the parent material behind precious coral and is not exclusive to the name 'precious coral'.
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
- Cleveland Museum of Art 1940.499coral
- The Met 2009.300.2984a–cSilk, linen, coral, metal, jet
- The Met 43.164Metal thread, coral beads
- Cleveland Museum of Art 1952.472jade and coral beads, pendants mounted in gold and enamel
- The Met 55.111.56Silver, enamel, coral
- Cleveland Museum of Art 1916.290silver, gilded; turquoise, coral and red glass
How it is identified
Precious coral can resemble lower-value corals, dyed coral, and plastic or bone imitations in colour and appearance, and unaided visual inspection struggles to distinguish natural from imitation or dyed products. Establishing the identity of such material is a laboratory task that relies on microscopic structural examination and spectroscopic instruments; the nomenclature sources provide no self-test criteria, and conclusions must be issued by an accredited laboratory.
Evidence grade AScope: Safety boundary: appearance is insufficient to decide natural or treated status; determination requires testing by an accredited laboratory.
Sources CIBJO Coral Blue Book 2024
Other research findings
Precious coral is the jewellery designation for the three Corallidae genera (Corallium, Pleurocorallium, Hemicorallium), including red, pink, orange and white varieties with a porcelain-like lustre, SG about 2.8 and hardness 3.
Evidence grade AScope: Defines precious coral as a collective name for three Corallidae genera; not a single species.
Sources CIBJO Coral Blue Book 2024
At China's request, four precious coral species were placed in CITES Appendix III (effective 01/07/2008): Corallium japonicum and the three species now placed in Pleurocorallium — P. elatius, P. konojoi and P. secundum (formerly Corallium); other kinds, such as Mediterranean coral (Corallium rubrum), appear in no CITES Appendix.
Evidence grade AScope: Distinguishes Appendix III species from unlisted ones; 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
- Precious coral is a collective name; the boundaries of red/pink/white varieties are treated in their own records.
- Note: Corallium etc. are CITES Appendix III (at China's request), not Appendix II; unlisted species (e.g. C. rubrum) are not CITES-controlled.
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
- Precious Coral (state the species and any treatments)
CIBJO Coral Blue Book 2024 §5.78, §5.28
Construction or treatment status
Natural identity; treatment status unknown
Treatments recorded for this material: Bleached (via parent material), Filled / Fracture-filled, 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
"Precious 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 · 5.78
What this means for you
Before buying, check the recommended listing name "Precious Coral (state the 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
- Last reviewed
- 2026-09-01
Trade-name ruling
- Laboratory identification required before the name is used.
- Suggested listing name
- Precious Coral (state the species and any treatments)
Care and wear
The normal care that applies to all corals, and so to Precious 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
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
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 |
|---|---|---|---|---|---|
| Bleaching | — | — | Optimization | — | — |
| Filling | — | — | Graded — see §5.4.1, Table 1 | — | — |
| Coating | — | — | Graded — see §5.4.1, Table 1 | — | — |
| Dyeing | — | — | Treatment | — | — |
| filling | — | — | — | filling | — |
| filling with the same material | — | — | — | filling with the same material | — |
“—” 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 Precious Coral, the name register records "Aka Coral", "Cerasuolo", "Deep Sea", "Garnet coral", "Miss", "Missu", "Misu", "Momo", "Momo Coral", "Sardinia Coral", "Satsuma" and "Shinkai", for which no restriction on use as a name is recorded (GB/T 16552 revision draft for comment (2023, not in force) Table A.3; GB/T 16552—2017 no occurrence of “Aka Coral” in the full text; CIBJO Coral Blue Book 2024 Annex C 7.7 “Cerasuolo”; CIBJO Coral Blue Book 2024 Annex C 7.7 “Deep Sea”; CIBJO Coral Blue Book 2024 Annex C 7.7 ““Garnet” coral”; CIBJO Coral Blue Book 2024 Annex C 7.7 “Miss”; CIBJO Coral Blue Book 2024 Annex C 7.7 “Missu”; CIBJO Coral Blue Book 2024 Annex C 7.7 “Misu”; CIBJO Coral Blue Book 2024 Annex C 7.7 “Momo”; GB/T 16552—2017 no occurrence of “Momo Coral” in the full text; GB/T 16552—2017 no occurrence of “Sardinia Coral” in the full text; CIBJO Coral Blue Book 2024 Annex C 7.7 “Satsuma”; CIBJO Coral Blue Book 2024 Annex C 7.7 “Shinkai”); 3 further names in non-Latin scripts are listed in the name register below (3 with no restriction recorded on use as a name).
Standard and listing namesThe formal naming counterpart of Precious Coral is coral in Table A.3 of GB/T 16552—2017, and the name Precious Coral itself is not listed in the standard; the suggested listing name is Precious Coral (state species and treatment). Names in four languagesNames are given in Simplified Chinese, Traditional Chinese, English (Precious Coral) and Japanese; the Japanese name shown is the entry's own, and the GSJ (Japan) wording for it is not yet verified by this site. Institution usageFTC records Coral and CIBJO records Precious Coral; GIA and Gem-A are unchecked and show the entry's own English name, which does not represent their position. Qualifications stripped from the heading name: FTC requires treatments to be disclosed and man-made products not to be called natural; CIBJO requires the genus to be stated, namely Corallium, Pleurocorallium or Hemicorallium. National standard namesGermany (RAL) writes Edelkoralle and the EU writes Precious Coral; CITES Appendix III covers only Corallium japonicum and Pleurocorallium elatius, konojoi and secundum, while Corallium rubrum and the Hemicorallium species are not listed. Candidate search termsThe GB/T 16552 revision draft for comment (2023, not in force) also lists Aka Coral, Momo Coral and Sardinia Coral, which are search candidates only; the full text of the current GB/T 16552—2017 has no corresponding names.
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 (15) | ||||
| Aka CoralEnglish | narrower name (variety or subtype) | search candidate only | no restriction recorded | GB/T 16552 revision draft for comment (2023, not in force) Table A.3; GB/T 16552—2017 no occurrence of “Aka Coral” in the full text; Note: Draft standard for comment, not in force. |
| CerasuoloEnglish | market name | matched automatically | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Cerasuolo” |
| Deep SeaEnglish | market name | search candidate only | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Deep Sea” |
| Garnet coralEnglish | market name | matched automatically | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 ““Garnet” coral” |
| MissEnglish | market name | search candidate only | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Miss” |
| MissuEnglish | market name | matched automatically | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Missu” |
| MisuEnglish | market name | matched automatically | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Misu” |
| MomoEnglish | market name | matched automatically | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Momo” |
| Momo CoralEnglish | narrower name (variety or subtype) | search candidate only | no restriction recorded | GB/T 16552 revision draft for comment (2023, not in force) Table A.3; GB/T 16552—2017 no occurrence of “Momo Coral” in the full text; Note: Draft standard for comment, not in force. |
| Sardinia CoralEnglish | narrower name (variety or subtype) | search candidate only | no restriction recorded | GB/T 16552 revision draft for comment (2023, not in force) Table A.3; GB/T 16552—2017 no occurrence of “Sardinia Coral” in the full text; Note: Draft standard for comment, not in force. |
| SatsumaEnglish | market name | search candidate only | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Satsuma” |
| ShinkaiEnglish | market name | matched automatically | no restriction recorded | CIBJO Coral Blue Book 2024 Annex C 7.7 “Shinkai” |
| 沙丁珊瑚Simplified Chinese | narrower name (variety or subtype) | search candidate only | no restriction recorded | GB/T 16552 revision draft for comment (2023, not in force) Table A.3; GB/T 16552—2017 the name does not occur anywhere in the text; Note: Draft standard for comment, not in force. |
| 莫莫珊瑚Simplified Chinese | narrower name (variety or subtype) | search candidate only | no restriction recorded | GB/T 16552 revision draft for comment (2023, not in force) Table A.3; GB/T 16552—2017 the name does not occur anywhere in the text; Note: Draft standard for comment, not in force. |
| 阿卡珊瑚Simplified Chinese | narrower name (variety or subtype) | search candidate only | no restriction recorded | GB/T 16552 revision draft for comment (2023, not in force) Table A.3; GB/T 16552—2017 the name does not occur anywhere in the text; Note: Draft standard for comment, not in force. |
How each authority words this name: see Names › Authority wording.
- GSJ (Japan) formal name
- 宝石サンゴ (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
- Red, pink or white coral of Corallium, Pleurocorallium or Hemicorallium genera
- Trade names and synonyms
- Cerasuolo (market name) · Momo (market name) · Satsuma (market name; conditional name) · Deep Sea (market name; conditional name) · Shinkai (market name) · Garnet coral (market name) · Miss (market name; conditional name) · Missu (market name) · Misu (market name) · Aka Coral (narrower name (variety or subtype); conditional name) · Momo Coral (narrower name (variety or subtype); conditional name) · Sardinia Coral (narrower name (variety or subtype); conditional name)
Four-language names
- 简体中文
- 贵珊瑚
- 繁體中文
- 貴珊瑚
- English
- Precious Coral
- 日本語
- 宝石サンゴ
National and regional formal names
- Germany (RAL)
- Edelkoralle (CITES Anhang III nur für Corallium japonicum sowie Pleurocorallium elatius/konojoi/secundum — alle vier in EU-Anhang C gemäß VO (EU) 2026/1383, in Kraft seit 29.06.2026; Corallium rubrum und die Hemicorallium-Arten sind weder gelistet noch in einem EU-Anhang)
- European Union
- Precious Coral (CITES Appendix III covers only Corallium japonicum and Pleurocorallium elatius / konojoi / secundum, all four in EU Annex C per Reg. (EU) 2026/1383, in force 2026-06-29; Corallium rubrum and the Hemicorallium species are not listed in any Appendix or Annex)
Qualifiers stripped from the headline name
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 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 | red, pink, white and others | filling (Filled / Fracture-filled); filling with the same material (Filled / Fracture-filled) | 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 material facts for Precious Coral, the industry definition in the CIBJO Blue Book — Coral Book 2024, which comes from an industry handbook rather than a national standard, limits Precious Coral to species of the family Corallidae, including Corallium, Pleurocorallium and Hemicorallium, gives a relative density of about 2.8 and Mohs hardness 3, and describes its distinctive feature as a persistent, intense red and/or pink or white skeleton with a porcelain-like lustre after polishing. The GB/T 16553—2017 records take values by class: for calcareous coral, Mohs hardness 3–4.5; density 2.6–2.7 g/cm³, this site noting that the cited clause gives 2.65 with tolerance ±0.05, from which the limits are derived; refractive index 1.48–1.66, this site noting that the cited clause gives the reading commonly obtained by the spot method, a typical value rather than an absolute limit; effervesces with a drop of hydrochloric acid when untreated. For coral as a whole (calcareous and horny): in calcareous coral the inorganic part is a cryptocrystalline aggregate and the organic part amorphous, and horny coral is amorphous; cleavage usually not seen on an aggregate; lustre waxy, vitreous on polished surfaces, when untreated.
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 Precious 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 Precious Coral (how to read class-level values).
Definition
Precious Coral: precious corals are those that are used in jewellery and decoration, specifically red, pink, orangey and white varieties with porcelain-like lustre after polishing. They are limited to species belonging to the family Corallidae, consisting of the three following groups: Corallium, Pleurocorallium and Hemicorallium. They have a specific gravity of approximately 2.8 and a hardness of 3 on Mohs scale. The distinguishing characteristic of precious coral, which is used in jewellery and ornamental products, is their durable and intense red colour, and or pink or white skeleton. Note — For more information regarding precious coral see clause (3.1.1.1) and clause (7.6).
CIBJO Coral Blue Book 2024
- Qualification
CIBJO trade definition from an institutional manual, not a national standard. The English text quotes the full definition at §5.78 of the Coral Blue Book 2024.
Source & check 2026-09-25
- Source
- CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.78, p.19 (locator checked 2026-09-25)
- Fact checked on
- 2026-09-25
Structure
Precious 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
Precious 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
Precious 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
Precious 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
Physical properties
Precious 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
Precious 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
Precious 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
Precious 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
Precious 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
Related CIBJO terms
- Aka
precious coral from the Corallium japonicum species that is found in Japan at depths of 80 to 300 m. It is dark red to very dark red with a white lengthwise interior, in fan-shape, with an average height of 5-30 cm, average trunk diameter of 5-25 mm and an average weight of 100-500 g. Same as moro or oxblood coral. Note— see Clause 2 Normative References; Convention on International Trade in Endangered Species of Wild Fauna and Flora.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.2, p.10
- Angel’s Skin
commercial name for a very rare anomalous (albino) light pink precious coral, notably from the Pleurocorallium elatius species (Japan and Taiwan) also known as boké or magai. In even more rare occasions, it may also occur in Corallium rubrum (known as “bello”, meaning beautiful) and in Corallium japonicum.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.4, p.11
- Cerasuolo
precious coral from the Pleurocorallium elatius species that is found in Japan and Taiwan at depths of 150 to 350 m. It may be bright red, salmon, orange, dark pink and flesh dark red to very dark red with a white lengthwise interior, in fan-shape, with an average height of 15-40 cm, average trunk diameter of 10-50 mm and an average weight of 100- 5000 g. Same as momo or satsuma. Note— see Clause 2 Normative References; Convention on International Trade in Endangered Species of Wild Fauna and Flora.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.18, p.12
- Non-living Coral
Precious coral that is collected as broken branches in sedimentary deposits (e.g. Sciacca coral) or harvested form the sea bed along with living corals (e.g. Pleurocorallium elatius in Japan).
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.31, p.14
- Deep Sea
precious coral from the Hemicorallium laauense species that is found in Midway, N/W around Emperor Seamount at depths of 1000 to 2000 m. It is usually variegated bright white, clear pink white pomegranate with red veins or spots, in fan-shape and parallel trunks, with an average height of 10-40 cm, average trunk diameter of 5-15 mm and an average weight of 50-250 g.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.32, p.14
- “Garnet” coral
precious coral from the Hemicorallium regale species that is found in Hawaii at depths of 350 to 600 m. It is usually purplish-pink, in parallel-shape, with an average height of 10-20 cm, average trunk diameter of 4-10 mm and an average weight of 50-150 g. Note — Not to be confused with the name of the garnet mineral group.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.42, p.15
- Mediterranean coral
precious coral from the Corallium rubrum species that is found mostly in the Mediterranean Sea as well as in the western Atlantic coast of northern Africa, Spain and Portugal at depths up to 1000 m. It has uniform red, orangey to pink uniform colour, in bush-shape, with an average height of 10-20 cm, average trunk diameter of 7 mm and an average weight of 50-200 g.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.61, p.17
- Midway
precious coral from the Pleurocorallium secundum species that is found in Hawaii and Midway sea mount at depths of 400 to 600 m. It may be uniform white-pink with small red speckles or veined white with pink, sometimes uniform clear pink, in fan-shape, with an average height of 10-30 cm, average trunk diameter of 8-20 mm and an average weight of 50-300 g. Same as rosato or white/pink coral. Note — see Clause 2 Normative References; Convention on International Trade in Endangered Species of Wild Fauna and Flora.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.62, p.17
- Misu or Missu
precious coral from the Hemicorallium sulcatum species that is found in the north of Philippines. at depths of 100 to 300 m. It is mostly white with thin skin of uniform pink, in long fan-shape, with an average height of 25 cm, average trunk diameter of 15 mm and an average weight of 200 g. Same as missu or miss.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.63, p.17
- Ornamental coral
precious coral that is used in objets d’art (5.70).
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.73, p.18
- Pure white
precious coral from the Pleurocorallium konojoi species that is found in South China Sea close to Vietnam at depths of 80 to 300 m. It is uniform white, in fan-shape, with an average height of 10-40 cm, average trunk diameter of 10-30 mm and an average weight of 100-700 g. Same as shiro. Note — see Clause 2 Normative References; Convention on International Trade in Endangered Species of Wild Fauna and Flora.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.80, p.19
- Sciacca
orangey, sometimes dark pink broken branches of Corallium rubrum from modern sedimentary deposits off the coast of Sciacca in southern Sicily, Italy, found at depths from 30 to 60 m. The branches are usually small in size, with an average branch size of 7-10 cm, and trunk diameter of 5 mm.
CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §5.86, p.20
Entries in the source that only point to another clause: Boké (§5.15, p.12) → §5.4 Angel’s Skin; Magai (§5.60, p.17) → §5.4 Angel’s Skin; Momo (§5.65, p.18) → §5.18 Cerasuolo; Moro (§5.66, p.18) → §5.2 Aka; Oxblood coral (§5.74, p.19) → §5.2 Aka; Rosato (§5.83, p.20) → §5.62 Midway; Sardinian coral (§5.84, p.20) → §5.61 Mediterranean coral; Satsuma (§5.85, p.20) → §5.18 Cerasuolo; Shiro (§5.88, p.20) → §5.80 Pure white; White/pink coral (§5.102, p.22) → §5.62 Midway
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 Precious 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
Precious Coral — 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
Precious Coral — criteria for distinction from other varieties: Precious corals are generally collected below 50 metres and live in ecosystems totally different from those of reef corals; common corals are hardly found in jewellery.
CIBJO Coral Blue Book 2024
- Treatment state
- untreated
- Qualification
Common corals may be used as adornment, typically after treatment such as polymer impregnation, bleaching or dyeing.
Source & check 2026-09-29
- Source
- CIBJO Blue Book — Coral Book (Coral Commission 2024) (CIBJO): §7.8 (Annex B, normative), p.28 (locator checked 2026-09-22)
- Fact checked on
- 2026-09-29
Each row's “Source & check” expands to the full source; the date beside it is the fact check date.
Clause-level definitions
Precious Coral is registered in the clause-level definitions under the entry name Precious Coral, on the basis of GB/T 16552-2017 Annex A, which defines it as red, pink or white coral of the three genera Corallium, Pleurocorallium and Hemicorallium. Cross-check result: listed directly in GB/T; not found under a standalone heading of the same name in CIBJO.
This table scrolls sideways on narrow screens.
| Term | Clause | Definition | Cross-check |
|---|---|---|---|
| Precious Coral | GB/T 16552-2017 Annex A | Red, pink or white coral of Corallium, Pleurocorallium or Hemicorallium genera | 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 (Precious Coral) is marked.
- Coral
Sub-entries (11)
This table scrolls sideways on narrow screens.
| Page | Content | Status |
|---|---|---|
| Browsing family | Coral materials | Live |
| Treatments recorded for this material | Bleached (via parent material), Filled / Fracture-filled, 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 Precious 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.