Antique jewellery using organic gems: Part II – red coral

I wanted to concentrate here on coral jewellery, particularly red coral. Coral has been used in carvings and decorations for thousands of years but it was not until the 13th and 14th centuries that it became used for rosaries and jewellery in Europe. Red coral (Corallium rubrum), also known as precious coral, became an industry centred around Italy and parts of France near Marseilles. Red coral is a sea grown coral, not a reef grown coral. Many of the harvesting practices such as dredging led to destruction and near extinction of the coral beds in and around the Mediterranean. Off Italy now, harvesting can only be done by hand under limited permits. Sardinia is still a major source of red coral and it is currently being harvested in areas in the Pacific Ocean.

While  Corallium rubrum coral is not listed in CITES, it is listed in some similar European Union Conventions.  China has listed four other Corallium species in Appendix III of the CITES Convention while black and blue corals are listed in Appendx II.

Because precious red coral has a hard, solid skeleton, it is able to be polished and carved for jewellery. It is often  used for cameos, as in the above pendant, as well as for beautiful drop earrings. It looks superb set in gold.

We talk about red coral but you can find lots of colour variations used in jewellery, ranging from a dark red, through to various shades of orange to a pale pink known as Angel Skin.

Apart from red precious coral and other members of the Corallium family of corals, there is also soft red coral (Melithaeidae) or Sponge Coral, that comes mainly from shallow reefs in the South China Sea. It is not included in CITES. This is used for a lot of modern jewellery. It is a orange-red colour, has a porous skeleton and needs to be impregnated with a form of resin to create a smooth surface able to be polished.  It is frequently dyed a darker red. The coral grows in a tree-like fan shape. There are also many imitants of coral – shell, glass, plastic  and reconstituted coral but most can be detected using a hand lens.