Though they all have the same crystal structure (cubic, like diamond and spinel), garnet is an entire group of minerals that vary in their chemical composition, resulting in a variety of gems featuring different colors and properties. Though some varieties of red garnet are common and found on nearly every continent on Earth, other garnets like orange spessartite, green demantoid and tsavorite, are much less abundant. There are more than 20 garnet species, but the five most important include pyrope and almandite (the combination of which creates rhodolite), spessartite, grossularite or grossularite (which includes hessonite and tsavorite), and andradite (which includes demantoid). Garnets of all species are the birthstone for January, so January babies aren't limited to the well-known red varieties.

January Birthstone