Spessartine Garnet is a silicate mineral and one of the rarest forms of Garnet. It is 6.5-7.5 on the Mohs hardness scale and is red to orange in color. When translucent, Spessartine Garnet is used as a gemstone. However, these translucent crystals are no longer mined from Navegadora Mine, in Minas Gerais. Brazil.