Mineral Species: Calcite and Quartz

Chemical Formula: CaCO3

Chemical Name: Calcium Carbonate

Mineral Class: Carbonate

Mineral Notes: Calcite is one of the commonest minerals, being the main constituent of limestone. Calcite is often fluorescent, a small amount of Managnese is enough to make it glow red under UV light. The mineral will bubble in acid distinguishing it from many similar species, even other carbonates which do not dissolve so easily in cold acids. 

Description: A bed of intermixed Calcite and Quartz crystals on a matrix of black basalt. Both minerals are white, transparent and very gemmy. The centre piece of the specimen is an almost 'floating' crystal of bipyramidal Quartz (photo inset). The form of the crystal and contrast of the minerals against the black basalt combine to make this a very attractive display specimen.

Location: Barrasford Quarry, Hexham, Northumberland, England.