Calc-Spar
the name usually given by mineralogists to carbonate of lime, rhombohedral in its crystallization. It dif- fers from aragonite only in crystallization. Calcite is one of the commonest tion. Calcite is one of the commonest this mineral. It is abundantly met with minerals. Marble, for example, is comminerals. Marble, for example, is com- posed of small crystalline granules of this mineral. It is abundantly met with in very many rocks as a secondary minin very many rocks as a secondary min- eral; that is to say, it is a decomposition product the result of the chemical aloccurs in the cracks, fissures, and vesteration of various rock-constituents, such as the feldspars. Thus it frequently occurs in the cracks, fissures, and vesland spar has often been given to calcite, at least to the finest colorless and transparent variety, because it is found in Iceland, filling up clefts and cavities spar is a lamellar variety, often with a in the basalt-rocks of that region. Slate and is found in Wicklow in Ireland, Glen spar is a lamellar variety, often with a Tilt in Scotland, and Kongsberg in Norway.