Hemimorphite is a zinc silicate mineral that is associated with zinc and lead ores. It was assumed to be the same mineral as smithsonite, which it closely resembles, and both were classified as calamine. However, it was discovered that they were in fact two different minerals, hemimorphite being a zinc silicate and smithsonite being a zinc carbonate. It most commonly forms as tabular crystals, fan-like clusters, or stalactitic and botryoidal aggregates. Hemimorphite is typically colorless, white, blue, green, gray or brown. This 78.7ct cabochon is an opaque greenish-blue color and is from Mexico.