UPDATING JEWELLERY CORALS

Coral is the term used to describe to a vast array of marine animals that are found throughout the world’s seas from freezing polar regions to equatorial reefs, and at all depths from the intertidal zone to the bottoms of the deepest oceanic trenches. The word coral is derived from the ancient Greek word korallion that was used to describe the historic precious red coral of the Mediterranean, known today as Corallium rubrum (Linaeus 1758). 

ABOUT CORALS
The corals are a loosely defined group of marine invertebrates (animals without backbones) that collectively belong to the phylum Cnidaria (Coelenterata), class Anthozoa . Animals of this class are characterised by their possession of a simple cup shaped body that consists of two layers of cells, and the presence of unique stinging cells, or cnidocytes, that are used both to capture prey and for defence. This class of coelenterates is subdivided into two subclasses. The first subclass, Alcyonaria (sometimes known as Octocorallia), contains soft corals (order Alcyonacea) including bamboo corals; gorgonian corals of the order Gorgonacea that include sea pens, sea fans, gold corals and pink to red calcific corallium corals; blue coral (order Coenothecalia (Helioporacea); and organ pipe coral (order Stolonifera). Alcyonarian corals have external polyps with eight tentacles, and their skeletons of are always internal (endoskeletons)—whether composed of separate or fused calcific spicules, or horny axial rods. Zoantrharia, the second subclass of the class Anthozoa contains the sea anemonies, the true (stony) reef-building corals that belong to the order Scleractinia, and the black, thorny corals that belong to the order Antipatharia. Reef building scleractinian corals are colonial, forming massive coral reefs from the external calcific skeletons (exoskeletons) that house individual polyps. In contrast, antipatharian corals are solitary, their six-tentacled polyps being located in a skin-like coenenchyme that surrounds the spiny, horny skeleton of this coral.

CORALS AND MAN
Precious corals have been used for the fabrication of items of jewellery and decoration since antiquity. Along with amber, precious coral may have also been used as currency for trade by Paleolithic man. As a renewable resource in the sea, precious corals are thought to be the slowest growing organisms of any known fishery past or present. Pink and red coral fisheries exist in the Mediterranean Sea and the Pacific Ocean. Black corals are distributed worldwide, and small fisheries for black coral exist in all oceans. Hence, precious corals represent a unique and interesting case history of a fishery which is very old and quite widespread and one which renews itself quite slowly.

Some corals are highly prized for the beautiful colours and shapes of their skeletons. Over the centuries these corals have been harvested by man for use in jewellery, decoration, and other souvenirs. Live corals and coral products such as coral rock, are also increasingly popular in the marine aquarium trade. The economic value of corals, and other coral reef animals, can encourage local communities to conserve coral reefs, but it is important that this trade does not endanger individual coral species or damage coral reef habitats. 

CORALS AND CITES
the international Convention on International Trade in Endangered Species (CITES) was initiated “to ensure that international trade in specimens of wild animals and plants does not threaten their survival”. Around 2000 species of coral are listed in Appendix II of this convention. This means that international trade in these species is regulated and monitored. Many countries now publish export quotas showing the amount of coral that can be traded each year. Between 1985 and 1997, CITES records show over 19,000 tonnes of coral were imported by 70 nations. 

CITES legislation applies to both commercial traders and to travellers bringing back live animals, or souvenirs such as jewellery and ornaments. Import and export of species listed in CITES requires special permits so that trade can be monitored. CITES export permits will only be issued when the relevant authorities are satisfied that the collection of the species did not endanger the species or affect their role in the ecosystem. 

It is illegal to bring CITES-listed coral, or coral artefacts such as jewellery, into any of the 158 countries which have signed the convention, without a CITES permit. This includes the UK, other countries in the European Community, the United States of America, Canada, and Australia. 

Without a permit, your souvenir or items of jewellery could be confiscated by customs officers. 

In addition to CITES, some countries or regions have other legislation regarding the collection and export of coral, and in some countries the export of coral is banned entirely. 

CITES listed corals in trade include:

Non-CITES listed corals in trade

* corals that have commercial use in jewellery

RED/PINK/WHITE PRECIOUS CORAL
Precious red to pink to white corals are solid, longitudinally striated calcitic corals that are derived from the endoskeletons of several species of corallium corals that belong to: 

Twenty-five species of corallium have been named, and six species are commonly traded.

Corallium rubrum

Red and pink corallium corals are branched and may be fan-like or bushy shaped. Colonies range in colour from bright red to pale pink or white and have white polyps. The endoskeleton of this coral is composed of stick-like calcium carbonate rods, which are 'sclerite', 'cross' and 'capstan' shaped, that have been fused together to form a rigid structure which may be coloured red, pink (due to carotenoid pigments deposited with the calcium carbonate) or white. These corals are very slow growing, and may grow less than 1mm per year as in Mediterranean red coral, and up to 8mm per year in Pacific Ocean species. They are also relatively long lived, attaining ages of up to 75 years old, and heights of up to 1 metre.

These species feed on small zooplankton and microplankton that are passively filtered from the water by the tentacles. Corallium corals have two types of polyps, one with eight feathery tentacles for feeding, and a second smaller type without tentacles which may help with the exchange of water. The polyps in red coral colonies are usually of one sex, and the eggs are fertilized and brooded inside the female polyps. Studies of Mediterranean red coral suggest that the larvae have a limited dispersal range. 

This coral grows on hard substrates and shows a preference for dark environments where there is little sedimentation. The Mediterranean red coral is found in depths of 10 to 280 metres, where it is often found in caves and crevices. The red and pink corals of the west Pacific are found at depths greater depths of 350 -1,500 m and occur mostly in areas with moderate to strong water currents.

Corallium sp nov.rubrum

Corallium rubrum (Mediterranean red coral) is endemic to the Mediterranean but is also present in some neighbouring Atlantic areas and the Cape Verde Islands. A number of other Corallium species such as the Hawaiian pink coral Corallium secundum, red coral (C. regale), pink coral (C. laauense), and Midway deep sea coral (Corallium sp nov.) occur in the Pacific Ocean.

Mediterranean red coral had been used for thousands of years in the production of jewellery, religious objects and medicine. This coral is still highly valued and used to produce jewellery and ornaments. Italy is the main producer of red coral objects. These corals were traditionally harvested using dredging equipment, which is non-selective and can cause widespread damage. Increasingly, red and pink corals are harvested using more selective methods such as SCUBA diving or submersibles. Because red and pink corals are slow-growing, they are vulnerable to over-exploitation and many known populations in both the Mediterranean and the Pacific have been over-harvested; yields from the Mediterranean have been reduced by 66 percent in the last 15 years. 

The use of the most destructive type of dredging equipment used in the Mediterranean, (known as the ingegno), has now been banned throughout the Mediterranean Sea. All non-selective fishing methods have also been banned in some parts of the Pacific, such as Hawaii. Many shallow water populations of Corallium rubrum, which are not of commercial quality, continue to thrive and reproduce in the Mediterranean. Management plans in both the Mediterranean and West Pacific aim to promote sustainable harvest by using measures such as calculating maximum sustainable yields, and limiting the size and number of colonies collected. A better understanding of the life history, ecology and population dynamics of red and pink corals will aid the development of effective long-term management plans for these species. 

Corallium rubrum (Mediterranean red coral), is listed in Annex V of the European Union Habitats Directive Pacific Corallium species are listed in the Fishery Management Plan of the Western Pacific Regional Fishery Management Council. This genus (corallium) is not listed in the CITES Convention, however, the species may be subject to domestic legislation which controls the collection of, or trade in, red and pink corals.

Identification
Precious coral, irrespective of its colour or origin, is identified in hand specimen by:

1. Its solid texture—with extremely few holes being visible in its polished external surface, other than a clusters of pin point holes that are the remnants of the coral’s central canal.

2. The presence of parallel longitudinal striations on the surface of the coral.

ANTIPATHARIAN BLACK CORAL
Antipatharian or thorny black corals are solid keratinous corals that form flexible endoskeletons. Various species of coral that belong to:

Antipathes grandis

Of the 150 species of this coral have been formally identified, 8 genera are subject to international trade. Commonly harvested species include Antipathes grandis, Antipathes dichotoma, and various Cirrhipathes sp. Individual species of antipatharian black coral may be either branching (bushy, feathery, fan-shaped, or bottlebrush shaped), or wire-like without branches (wire or whip corals). The polyps are small (0.5-5 mm ) and have six non-retractable tentacles. Live colonies are usually white, yellow, orange, red or green. The brown to black endoskeleton of this coral is covered in tiny spines that can range in size from about 0.04 to 0.6 mm. The size, shape and density of these spines, along with the pattern of branching of the colony and the appearance of the polyps, are used to identify species in this group. Colonies may reach up to 1.8 m in height. 

Antipatharians black corals are found worldwide, but are most common in the Indo-Pacific and Caribbean regions. They grow at a wide range of depths, from 1 - 6000 m, but most are found between 30 and 80 m. They tend to be associated with low light conditions, either in deep water, or in turbid or shaded areas of shallow water. Black corals are frequently found where there are strong currents. 

All antipatharian black corals are colonial with a rigid, rod-like skeleton made of protein. There are no calcareous components in the skeleton, and unlike gorgonian corals there are no calcareous spines (spicules or sclerites) in the soft tissues. Individual colonies are either male or female and feed by capturing zooplankton from the water. Colonies are slow-growing and long-lived. They form an important habitat for other species and support unique communities of marine life.

These black corals have been used for centuries both for charms and as medicine. The skeletons of black corals are still highly prized and are used in jewellery or sold as curios. These species are mainly collected by divers but in some areas may be harvested by submersibles or with non-selective net dredges. A small aquarium trade in live specimens has also been reported. Black corals are valuable and are therefore subject to considerable collecting pressure. Populations are slow to recover because they grow slowly and take a long time to reach sexual maturity. Black coral may be globally threatened but data on status and trends are limited.

Antipatharian black corals are listed in Appendix II of the Convention on International Trade in Endangered Species (CITES) , therefore trade in this species is regulated. A valid CITES export permit from the country of origin is required to bring black coral or objects made from black coral, such as jewellery, into the 158 countries that have ratified the CITES convention. In addition to CITES the export of black coral is banned or restricted by a number of countries. Black coral collection in some locations such as Hawaii is carefully managed to ensure that collection is sustainable. Black corals have been traditionally difficult to study because they live in deep water, however, a research programme in Hawaii has been running since 1970. Submersible craft are now used to investigate the ecology and distribution of black coral species. Black corals may form part of the marine community in Marine Protected Areas or areas where management plans are in place to protect the coral community.

Identification
Black (organic) antipatharian or thorny coral is identified by:

1. Its tree-like structure in cross-section.

2. Observation of remnants of radial spines often visible when polished surfaces of
   this black coral are examined in tangential illumination with magnification. White
   light is transmitted through thin superficial layers of this coral to gives these 
   layers a waxy brownish red colour against which the presence of spines is 
   immediately obvious. 

3. Noticing a ‘salty burnt hair’ aroma when a hot point is judiciously applied to the
   surface of this coral.

4. Determining a specific gravity of 1.34/1.35 for the material.

BAMBOO CORALS
Bamboo corals are a group of flexible corals that have endoskeletons that consist of alternating white calcitic internodes and brownish to black nodes of keratin (gorgonin). At lease four genera of bamboo corals have been identified. These corals belong to: 

Bamboo corals belong to the Family Isididae of the Order Alcyonacea within the Subclass Alcyonaria (Octocorallia) . Isidids are octocorals, meaning they have eight pinnate tentacles on each polyp that can be either retractile (can be drawn in) or non-retractile. The bony calcareous internodes of their skeleton, which are composed of fused sclerites, are interspersed with proteinaceous gorgonin (nodes) that are not composed of fused sclerites. This structure gives the skeletal remains of the organism an eerie fingerlike appearance. 

Drs. Frederick Bayer and Stephen Cairns of the Smithsonian Institute in Washington D.C., estimate 38 genera and 138 recent species within the family Isididae worldwide. Two ways to distinguish between species are by morphology (the body shape) or by the sclerites, which are small calcareous structures in the tissue of the polyps. To identify a sclerite, a scientist needs three things—a preserved tissue sample, a scanning electron microscope, and a trained eye.

Very little is known about bamboo corals. However, they do form a habitat for associated species, including crabs and larval fish. On the relatively barren seamount plains, one meter of structural relief can improve the survival rates of these associated species by providing refuge, settlement substrate, and/or a feeding perch. Similar to trees in the forest that perform a similar function for birds, corals perform this function for reef fish and some invertebrates.

Traditionally, Isidids in the subfamily Keratoisidinae have been identified by their branching morphology. The polyps are not retractile, and the sclerites of the polyps are large spindles, needles or rods, arranged longitudinally, and smaller rods or scales arranged irregularly. Sclerite identification can be time-consuming and expensive. Therefore, Frederick Bayer devised a morphological key to identify the four species that exhibit these qualities. Each has a different shape.

Keratoisis sp.		Acanella sp.
Lepidis olapa		Isidella sp.

Lepidisis colonies are unbranched, like sea whips, but they have an axis of proteinaceous nodes and calcareous internodes. Lepidisis is the only documented unbranched genera of Keratoisidinae. 

There are three branched genera of Isidids. 

In Keratoisis the branches arise from the nodes. 

In Isidella, the branches arise from the internodes, and the colonies are flat and spreading like candelabra. 

In Acanella, the branches also arise from the internodes, but the colonies are bushy, and branch in whorls.

However, undetermined species of bamboo coral have been desctibed in which branching occurs both at their nodes and internodes.

Identification
This attractive jewellery coral is identified, in hand specimen, by its alternating structure of short brownish keratinous (black coral) nodes and longer calcitic internodes. Examination with the 10x hand lens will reveal: 

1. The longitudinal striations on its solid white coral internodes.

2. Firm attachment of the ‘black coral’ nodes to the white coral internodes.

3. The concentric lamellar structure of the keratinous internodes.

When the internodes of bamboo coral are dyed red or pink, this colour enhanced coral can be difficult to discriminate from corallium precious coral—unless evidence of residual dye and /or wax is observed.

GOLD CORALS
Gold corals consist of a little studied group of deep water corals that have golden coloured keratinous endoskeletons. The few studied species belong to :

The gold corals consist of a at least four species of deep water corals that secrete a gold coloured keratinous endoskeleton. These corals secrete only protein and no calcite. In addition, gold coral is a parasite, whereby its larval stages settle out on other species of corals, particularly bamboo corals. Eventually, the gold coral overgrows the entire bamboo coral ‘tree’ incorporating the bamboo coral's skeleton as the core of its own skeleton. Gold and bamboo corals also have another interesting characteristic: They are bioluminescent. These corals light up in a beautiful show of sparkling blue lights when mechanically stimulated, such as when the current is strong or when a crab walks down one of their branches. Perhaps it attracts the small animals they feed on; no one really knows for sure.

Calyptrophora sp.		Gerardia sp.
Callogorgia sp.

Of the gold corals, for several decades Gerardia sp. has been commercially harvested from the deep (300-400 m) waters off Hawaii and the line of seamounts that lie to the northwest. The flattened, branched colonies, that may reach a height of 250 cm, are the major commercial source of gold coral. Another possible sources of gold coral in the deep waters of the Indo-Pacific region include Narella sp. that has 100 cm² fans that often have a surface area of 1.5 m². Smaller gold corals, such as Calyptrophora sp. have poor commercial prospects as its branches areonly 1-10 mm thick and up to 30 cm long. At the present time the commercial significance of Callogorgia gilberti has not been established.

Identification
Gold corals are usually readily identifiable by 10x hand lens examination by:

1. Noting the tree-like structure in cross-section of this organic coral.

2. Observing the characteristic dimpled or longitudinally ridged golden surface of
   this coral. 

3. Noticing a ‘burnt hair’ aroma when a hot point is judiciously applied to the
   surface of the coral.

HELIOPORA (BLUE) CORAL
Heliopora coral is a natural coloured blue calcitic coral that has limited value in jewellery due to its intrinsic porosity. This coral belongs to:

Colonies of H. coeruela can be tree-like, plate-like or column-like. The skeleton is dense and blue in colour. Living colonies are brown, or greenish-grey (2,3) with minute transparent polyps of < 1 mm size. Blue coral has a calcified skeleton that may attain a height of several metres, but does not belong to the order Scleractinia. This coral is a relatively common reef-building coral.

The blue skeleton of Heliopora coerulea is caused by the deposition of iron salts in the calcium carbonate skeleton. Blue coral is an important reef-building coral in some areas of the Indo-Pacific oceans, with the largest colonies being found in Japan. Blue coral colonies in the Indian Ocean can also reach several metres in diameter and may cover large areas. Like other reef-building corals, blue coral contains symbiotic algae known as zooxanthellae that provide the coral polyps with nutrients. The polyps of H. coerulea extend from pores in the skeletons surface and capture plankton and organic particles from the water with their tentacles. 

Blue coral is harvested for the live aquarium trade, and may form part of 'coral rock'. The blue skeleton is also popular in the marine curio trade and is made into jewellery and ornaments. Blue coral, like other coral species, may be threatened by pollution, destructive fishing practices, unsustainable tourism and global climate change. 

As blue coral is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES). International trade in live or dead specimens is regulated and subject to licencing. Trade without such permits is likely to constitute a criminal offence. In addition to CITES requirements, regions and countries may have legislation banning or limiting the collection or trade of blue coral.

Identification
H. coerulea blue coral is identified in hand specimen, and under the 10x hand lens examination, by:

1. Its porous, relatively smooth surface that has pores of two size—large pores of 0.7-1.0 mm diameter, and small pored of 0.1 mm diameter)

2. The possession on a natural blue colour that can deepen at depth in the coral. 

References: 

• Brown, G. (1976) Two new precious corals from hawaii. Australian Gemmologist. 12, 371-377.

• Brown, G. (1988) Bamboo coral: A new precious coral from Hawaii. Australian Gemmologist. 16, 449-454.

• Grigg, R. & Brown, G. (1991) Tasmanian gem corals. Australian Gemmologist. 17, 399-404.

• www.arkdive.com

• www.oceanexplorer.noaa.gov

• www.wpacfin.nmfs.hawaii.edu