Calcite Anduze France

Calcite personal find at the quarry of Anduze in France year 2007

Chemical composition: CaCO₃ calcium carbonate

Hardness: 3

How to identify calcite

Calcite can be easily identified by a few simple tests:

Hardness test: It is relatively soft, with a hardness of 3 on the Mohs scale.

Acid reaction: Calcite reacts vigorously with dilute acids, such as hydrochloric acid, producing bubbles of carbon dioxide.

Optical properties: Depending on the angle at which it is viewed, calcite exhibits a noticeable double refraction, meaning that when viewed through a calcite crystal, images are doubled.