Calcite

Calcite is a common and widely distributed mineral. It is a rock-forming mineral that is a major constituent in calcareous sedimentary rocks (limestone) and metamorphic rocks (marble). It may be precipitated directly from seawater and it forms the shells of many living organisms, which on death accumulate to form limestone. In areas of hot springs…

Ruby

Ruby is the fabulous gemstone for those born in the month of July. Ruby is the superb scarlet variety of corundum, the second hardest natural mineral known.The non-red variety of corundum is sapphire. Sapphires are well known as being blue, but they can be nearly any colour. The red colour in ruby is caused by…