Dioptase is a gorgeous, intense green mineral that forms in desert regions as a secondary mineral. It has a hardness of 5 and its chemical formula is CuSiO3·H2O. A fun fact is that human tooth enamel...

Calcite is a common but spectacular mineral. Its formula is CaCO3, and it is a trigonal-rhombohedral mineral. This crystal structure takes on many different forms - over 300 of them! Here’s a fun fact:...

Emerald, a favorite among precious gems, is actually a variety of beryl. The pronunciation of beryl is the same as if you were saying “barrel.” Other common names for beryl include aquamarine (blue),...