The CIBJO Coral Book is one volume in the series of reference documents collectively known as the CIBJO Blue Books, published by the World Jewellery Confederation (Confédération Internationale de la Bijouterie, Joaillerie, Orfèvrerie des Diamants, Perles et Pierres). It establishes internationally recognised standards for the nomenclature, classification, treatment disclosure, and ethical sourcing of coral used in jewellery and ornamental objects. Alongside companion volumes covering diamonds, coloured gemstones, pearls, and precious metals, the Coral Book forms part of a harmonised framework that trade associations, gemmological laboratories, and national regulatory bodies worldwide are encouraged to adopt as a baseline for responsible commerce.

Purpose and Authority

CIBJO was founded in 1926 and today represents national jewellery trade associations across more than forty countries. Its Blue Book series functions as a living set of industry standards rather than a static code: each volume is reviewed and updated periodically by specialist technical committees, with revised editions ratified at the annual CIBJO Congress. The Coral Book addresses a material that sits at the intersection of gemmology, marine biology, international conservation law, and consumer-protection regulation — a complexity that makes standardised guidance especially important. Without a shared vocabulary and disclosure framework, the same piece of treated or imitation coral could be described in contradictory terms by different sellers in different markets, undermining both consumer confidence and conservation efforts.

Scope: Species and Nomenclature

The Coral Book recognises several distinct categories of coral used in jewellery, each with defined acceptable trade names:

• Precious coral (Corallium spp., principally Corallium rubrum from the Mediterranean and Corallium japonicum and related species from the Pacific): the classic red-to-pink skeletal coral used in high jewellery since antiquity. The document specifies that the unqualified term "precious coral" may only be applied to material from the genus Corallium.
• Black coral (order Antipatharia): a proteinaceous, horn-like organic material, typically dark brown to black, used in carved and beaded jewellery particularly in Hawaii and the Caribbean. The Coral Book requires the name "black coral" to be accompanied by disclosure of any bleaching or dyeing that alters the natural colour.
• Bamboo coral (family Isididae): a deep-water coral with a segmented skeletal structure. Because bamboo coral is frequently dyed to simulate the appearance of precious coral, the Coral Book places particular emphasis on disclosure requirements for this material.
• Gold coral (Gerardia spp.) and other less commercially significant species are addressed where relevant trade use has been documented.

The document further distinguishes between natural coral (untreated), treated coral, assembled or composite coral, and imitation coral — a hierarchy that mirrors the classification logic applied to gemstones throughout the Blue Book series.

Treatment Disclosure Requirements

Coral is among the most heavily treated of all organic gem materials, and the Coral Book's treatment-disclosure provisions are correspondingly detailed. The principal treatments addressed are:

• Dyeing: The application of colourants to alter or intensify the natural hue. Dyed coral must be disclosed as such; the term "colour enhanced" is not considered a sufficient substitute for explicit disclosure of dyeing.
• Bleaching: Used primarily on black coral to produce a golden or honey-coloured material sometimes sold as "gold coral." The Coral Book requires disclosure whenever bleaching has materially altered the natural colour.
• Impregnation: The filling of surface-reaching fractures or porous areas with resins, waxes, or polymers to improve durability or apparent clarity. Impregnated coral must be identified as treated, with the nature of the impregnating substance disclosed where determinable.
• Bleaching combined with dyeing: A two-stage process sometimes applied to lower-grade bamboo or other coral to simulate the appearance of high-quality Corallium. This compound treatment requires compound disclosure.

The Coral Book aligns its treatment terminology with the broader CIBJO framework, which in turn draws on internationally recognised gemmological practice. Laboratories issuing coral identification reports are expected to use the same disclosure language, facilitating consistent communication between sellers, buyers, and regulators.

Imitation and Composite Materials

The document defines imitation coral as any non-coral material — including dyed calcite, dyed bone, glass, plastic, or synthetic resin — that is fashioned or coloured to resemble coral. Such materials must never be sold under the name "coral" without a clear qualifier (e.g., "imitation coral" or "simulated coral"). Composite coral, in which genuine coral is combined with a non-coral substrate or bonded with a significant quantity of filler, must similarly be identified as composite rather than natural coral. These provisions are designed to prevent the substitution of inexpensive simulants for genuine material in a market where the price differential between, say, high-quality Corallium rubrum and a dyed bamboo coral or resin imitation can be very substantial.

CITES Compliance and Legal Trade

One of the most distinctive features of the Coral Book, compared with companion volumes covering mineral gemstones, is its integration of international conservation law. Several coral species are listed under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Corallium species have been the subject of repeated CITES listing proposals, and the regulatory landscape continues to evolve. The Coral Book advises that traders must be aware of the CITES status of any coral species they handle and must comply with applicable permit and documentation requirements for import, export, and re-export.

The document does not itself constitute a legal instrument — CITES compliance is governed by national implementing legislation in each signatory state — but it provides a framework for due diligence and documentation that supports legal trade. Traders are encouraged to retain provenance documentation demonstrating that coral was harvested or acquired in accordance with applicable regulations, and gemmological laboratories are advised to note any CITES-relevant species identification on reports where the species can be determined.

Adoption and Practical Application

The Coral Book is formally adopted or referenced by CIBJO's member national associations, which include organisations such as the British Jewellers' Association, the Jewelers of America, and equivalent bodies in Italy, Japan, Germany, and elsewhere. Gemmological laboratories — including those affiliated with GIA, the Gübelin Gem Lab, and Gemmological Institute of Thailand — are expected to align their coral-report terminology with CIBJO standards, though individual laboratories may supplement the framework with additional technical detail.

In practice, the Coral Book's greatest day-to-day relevance is felt in three areas: retail disclosure at point of sale, laboratory report language, and customs and import documentation. Retailers selling treated coral are required, under the standards, to disclose treatment at the time of sale; failure to do so constitutes misrepresentation under both the CIBJO framework and the consumer-protection legislation of most major markets. Laboratory reports that follow CIBJO terminology allow buyers, insurers, and estate appraisers to interpret findings consistently regardless of which laboratory issued the report.

Periodic Revision

Like all Blue Book volumes, the Coral Book is subject to revision as scientific understanding, trade practices, and regulatory requirements evolve. Updates may be prompted by new detection methods for previously unidentifiable treatments, changes in CITES listings, the emergence of new simulant materials, or shifts in the commercial importance of particular coral species. Stakeholders — including trade associations, laboratories, and conservation bodies — may submit technical input to CIBJO's specialist committees ahead of each revision cycle. The current version of any Blue Book volume is available through CIBJO's official publications channels.

Further Reading

• CIBJO Blue Book series (official publications)
• GIA — Coral gem overview
• CITES Appendices — current listings