Calcit

The name Calcite derives from the Latin name calcs – turning into powder by heating, used also as a name for the lime. Well known and widely used mineral with a simple chemical composition - CaCO3 and polygenic origin. This is a mineral, that feels equally well everywhere. It forms beautiful crystals (the dream of every collector) when mixed with hot aqueous solutions. It can create huge limestone formation layers or grow through large granular masses under the influence of temperature rise and pressures in the crust, turning the limestone into beautiful marble.

In its pure form this mineral is colourless to white and transparent, often contains impurities (ferrum calcite, manganese calcite, cobalt calcite, etc.), which stain it in different colours and make it cloudy and dense.

Calcit can be found in the form of granular aggregates (marble and limestone), solid or fibrous masses (denoted also as "silky spar"), stalactite, oolitic, coral shaped to earthy or dusty fractured.
The varieties of calcite crystals are extremely diverse. Known are more than 600 basic forms of calcium - acute to obtuse rhombohedra, tabular forms, prisms, or various scalenohedra. Calcite druses are great collector's material.

Calcite crystals have the following properties - trigonal-rhombohedral, hardness – 3, perfect cleavage. A characteristic feature of the transparent calcite crystal is its ability to double the objects seen through (eg printed text) due to the strong and different refraction of light rays inside it. These properties are used in optical devices technology (eg polarizing microscope).

Limestones and marbles are widely used as a construction cladding material, as a flux in the metallurgy and as a raw material for lime.
The largest deposits of calcite have been found in Iceland - homeland to the biggest calcite crystal with dimensions 6x2m. Large deposits of calcite exist in Eastern Siberia and South Africa.
In Bulgaria the best-shaped calcite crystals can be found in the hydrothermal veins from Burgas region and the Rhodopes Mountain.

Petya Yordanova