Hardness : 7
Specific Gravity : 2.65
Refractive index : 1.54 - 1.5
Doubly Refracting (bi-refraction) : 0.009
Citrine, also called citrine quartz or citrine topaz, is an amber-colored gemstone. It is a form of quartz with ferric iron impurities, and is rarely found naturally. Most commercial citrine is in fact artificially heated amethyst or smoky quartz. Brazil is the leading producer of naturally mined citrine, with much of its production coming from the state of Rio Grande do Sul.