Coral
珊瑚／サンゴ
珊瑚
Coral
Corail
Glossary
Thematic
Jewellery, Material
The skeleton of a marine animal. Coral polyps secrete a strong calcium structure that was often used for watch dials. It s colour ranges from pale pink (called angelskin coral) to orange to red to white to black. Coral has a hardness of about 3.5 and a specific gravity of 2.6 to 2.7.