The facts
What black Coral actually is
Black Coral is classified as horny proteinaceous skeleton of antipatharian corals - not carbonate at all, with the composition Chitin-protein complex with scleroprotein; essentially organic. It crystallises in the amorphous / concentric organic layering system.
Colour comes from melanin-type pigment in the protein matrix, which is also what a laboratory looks at when it is asked whether a colour is natural.
Refractive index 1.56 (spot). Specific gravity around 1.34-1.46. Cleavage: none; splintery. Those three numbers separate it from most of what imitates it.
Where black Coral comes from
Black Coral is produced at Auau Channel off Maui and Lanai, Hawaii, USA (the licensed, quota-managed fishery), Sulawesi and Sumbawa, Indonesia, Cebu and Palawan, Philippines and Cozumel and the Caribbean (heavily depleted).
The locality is part of the description, not a footnote — two stones of the same weight from two of these places are not the same stone.
How black Coral is treated
CITES APPENDIX II for all Antipatharia - permits required for every international movement, in raw or worked form. Routinely heat-softened and pressed into shape, bleached to produce 'golden' coral, and moulded. Burns with an acrid hair/horn smell, which is diagnostic. Much Indonesian and Philippine material moves without permits; buyers should expect seizure risk.
Treatment changes value, sometimes by a multiple, so it belongs in the description before the price and not after the sale.
What black Coral is confused with
In the trade black Coral is most often mistaken for, or substituted by, Horn and bone dyed black, Black plastic and vulcanite, Dyed bamboo coral or Genuine golden coral.
The separation is rarely a matter of opinion: refractive index 1.56 (spot) and specific gravity 1.34-1.46 settle most of it in a minute, and magnification settles the rest.
What black Coral is used for
Demand for black Coral comes from jewellery, carving and sculpture and decorative objects, which is why one price per carat never covers it.
We quote each application in the unit that trade actually buys in, by the carat, by the block or by the piece.
Durability and care
Hardness 2.5-3.5; cleavage none; splintery. That combination decides what it can safely be set into.
Below about 5.5 a stone will be scratched by ordinary household dust, which is largely quartz. That does not make it unusable — it makes it a pendant, an earring or an object rather than a ring worn every day.
Warm water, mild soap and a soft brush. Avoid ultrasonic cleaners on anything fracture-filled, stabilised, dyed or visibly included.
What black Coral costs
As a guide, black Coral trades around $5-80 per gram worked; Hawaiian licensed material commands a substantial premium.
That is a range, not a quote. Colour, size, clarity, cut and origin move the figure a long way inside it, and the only honest price is one given against a specific stone. Send us what you need and we will price it.
Questions
Is black Coral treated, and how?
CITES APPENDIX II for all Antipatharia - permits required for every international movement, in raw or worked form. Routinely heat-softened and pressed into shape, bleached to produce 'golden' coral, and moulded. Burns with an acrid hair/horn smell, which is diagnostic. Much Indonesian and Philippine material moves without permits; buyers should expect seizure risk.
Where does black Coral come from?
Auau Channel off Maui and Lanai, Hawaii, USA (the licensed, quota-managed fishery), Sulawesi and Sumbawa, Indonesia, Cebu and Palawan, Philippines and Cozumel and the Caribbean (heavily depleted). Origin affects price, so we name the locality rather than the country on every quote.
Is black Coral hard enough to wear every day?
Not really. At 2.5-3.5 on the Mohs scale it is softer than the quartz dust in ordinary household dirt, so it scratches with wear. It suits pendants, earrings and objects better than a daily ring.
How much does black Coral cost?
Indicatively $5-80 per gram worked; Hawaiian licensed material commands a substantial premium. Colour, size, clarity and origin move the price a long way within that, so treat it as a range and ask for a quote against a specific stone.
What is black Coral confused with?
Most often Horn and bone dyed black, Black plastic and vulcanite, Dyed bamboo coral and Genuine golden coral. A refractive index of 1.56 (spot) and a specific gravity near 1.34-1.46 separate it quickly.
What is black Coral used for besides jewellery?
carving and sculpture and decorative objects. Each of those trades buys it in a different form and a different unit.
Related stones
Looking for black coral?
Tell us the size, the quality and what it is for. We source it, photograph it and quote it — with the locality named.
Ask about black coral