Calcite is one of the most common minerals which grows in a wide variety of different shapes, colors and translucencies. The mineral itself actually belongs to a calcite group of "related carbonates" that are "isomorphous" with each other. All members of the group crystalize in triangular formations, have perfect rhombohedron cleavages, and in transparent rhombohedrons, display strong double refractions. Unique Calcite formations are created inside the caves where calcium rich water penetrates the cavern's limestone enclosure and slowly drips and flows on top of itself, allowing for the formation of unique stalactite and other globular formations to be created. In this slow process, other minerals can intermix with each other, adding to the interest and forming unusual specimens. Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (CaCO3). Calcite has the hardness of 2.5-3 on the Moh's scale.