Coquina

About it

Loosely cemented limestone made almost entirely of whole and broken shells, easy to see by eye. Quarried in Florida, where the Castillo de San Marcos in St. Augustine is built of it.

Type

Rock (sedimentary)

Group

Sedimentary (biochemical)

Lustre

dull

Colours

tan, cream, white, orange-brown

Transparency

opaque

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