5x6x3.75" smokey quartz matrix contains two hexagonal aquamarine crystals w/strong blue coloring, one measuring 3" long while other measures 4.5" long. Quartz is an abundant mineral in the Earth's continental crust. There are many different varieties of quartz, several of which are semi-precious gemstones. Throughout the world, varieties of quartz have been, since antiquity, the most commonly used minerals in the making of jewelry and hardstone carvings. Smokey quartz's appearance is created by being exposed to millions of years of residual radiation. The quartz matrix is intersected by aquamarine, a blue or turquoise variety of beryl (a mineral composed of beryllium aluminium cyclosilicate), occurring at most localities which yield ordinary beryl. This example was excavated in the northeastern Brazilian state of Rio Grande do Norte. Wonderful display.