Rainbow Calcite

Bright red and white bands of Calcite and Aragonite sit atop a layer of mossy green Calcite points in this fun stone specimen from Mexico. 

The change in colors are a result of layered deposition in which different "impurities", like iron-inclusions, create color variations and lovely patterns within the stone. Because of the alternating bands of color, this type of Calcite is often referred to as "Rainbow" Calcite. 

Calcite can form in a variety of colors and shapes. This piece formed in a massive-style deposit. Rather than forming into individual single crystals, the Calcite formed in a large vein, allowing it to be removed as larger pieces or "masses". The smooth, high-shine finish on this piece, and on many massive calcite specimens from Mexico, comes from two factors: calcite's natural waxy-to-vitreous luster and a standard mineral preparation process called acid-washing. During preparation, the rough specimen is dipped briefly in dilute acid. This both cleans the rock, and dissolves tiny surface micro-fractures and crumbles, leaving behind a smoother surface without adding any foreign materials, oils, or synthetic coatings to the stone. 

This specimen displays well from multiple angles, and even fluoresces under UV light!

Please note: A thin layer of iron-rich Hematite is also present in this specimen. It is possible when touching the darker, hematite-rich areas of the specimen to find a rust-like coloration on your fingers. You can wash your hands with soap and water to remove.