Characteristics of Coral:

Chemical Name: Calcium carbonate

Formula: CaCO3

Colors: Pale pink, orange, red

Structure: Rhombohedral

Hardness: 3.5

Specific Gravity: 2.6-2.7

Refractive Index: 1.48-1.66

Lustre: Vitreous, waxy

Streak: White

Locations: Warm seas around Japan and Malaysia, Mediterranean, African coastal waters

What is Coral? 

Precious (red) Coral includes species such as Corallium Rubrum and Corallium Japonicum and is found in tropical and semi-tropical waters. Precious Coral is valued over other types of Coral for its toughness and attractive pink to red hues. Coral is the exoskeleton of the marine polyp – a small creature that secrets calcium carbonate to form branchlike structures. As the branches tend to be fine and narrow, material is usually sourced from the thicker forks. Coral has been used decoratively since prehistoric times.