Calcite. Cregiau quarry.

Calcite. Cregiau quarry.

Calcite, Calcium carbonate, CaCO3  This is one of several specimens collected from Cregiau quarry, near Pentyrch in South wales. A scattering of milky white crystals, mostly nailhead crystals, with a number of rhomboid crystals, are sitting on a bed of light brown calcite. The bed of brown calcite is in a form which is hard to describe, but seems to be rosettes made up of small bladed crystals growing in a haphazard arrangement.