<b></b><b>Smoky quartz is a brown <b>to black variety of quartz<b>. </b></b></b>Like other quartz gems, it is a silicon dioxide crystal. The smoky color results from free silicon, formed from the silicon dioxide by natural irradiation. Quartz is about a 7 on the Mohs Scale. We reserve the right to substitute these individual pieces with material of equal or greater value. These pictures are not to scale so please read each description for the actual size.