Pirate Gold Coins Treasures of the Earth is pleased to offer this absolutely gorgeous Smokey Quartz piece with Tourmaline Crstals going THRU the quartz! Absolutely stunning! (4x12) Smokey quartz is a grey, translucent variety of quartz that ranges in clarity from almost completely transparent to almost opaque browish gray or black crystal. Like other quartz gems, it is a silicon dioxide crystal.