Coral

About it

Skeleton of precious coral, mostly Corallium from the Mediterranean and western Pacific, with fine wavy growth lines. Many corals are protected under CITES, so check the rules before buying or shipping.

Type

Organic gem

Group

Coral skeleton (calcite)

Hardness (Mohs)

3–4

Specific gravity

2.6–2.7

Lustre

vitreous (glassy), waxy

Colours

red, pink, orange, white

Transparency

opaque, translucent

Cleavage and fracture

none; uneven to splintery fracture

Typical values: real specimens vary. For more, see mindat.org.