Mother of pearl

About it

The iridescent inner lining of shells such as pearl oysters, abalone, and freshwater mussels, made of the same nacre as pearls. Cut for inlay, buttons, and beads.

Type

Organic gem

Group

Mollusc shell (nacre)

Hardness (Mohs)

3–4

Specific gravity

2.6–2.8

Lustre

pearly

Colours

white, cream, silver, pink, grey, iridescent

Transparency

opaque, translucent

Cleavage and fracture

none; layered, uneven fracture

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