This calcium carbonate will form during any type of geological event. While considered very common, the variety of ways this crystal can form is far from that. Over 300 different crystal formations have been identified, which can combine to create thousands of variations on the Calcite theme. This crystal grows in a double pyramid or dipyramid with an elongated point resembling a dog's tooth. Cave formations like Stalactites, Stalagmites, Soda Straws, Cave Pearls, etc. are also types of Calcite formations.
Calcite has an important environmental impact.
By utilizing the carbon dioxides in the water to accomplish this, more CO2 is pulled from the atmosphere to dissolve in the ocean creating a carbon dioxide filter for the planet. Helping to alleviate the green house effect. Some theories contend this CO2 filtering process was an important factor in creating an inhabitable Earth. Clear specimens of Calcite are referred to as Iceland Spar, even though the majority of these pieces now come from Mexico. This clear crystal has a unique double refraction quality.