Stone or rock, is a naturally occurring solid aggregate of one or more minerals or mineraloids. They have been used by mankind throughout history. From the Stone Age, stones have been used for tools. The minerals and metals found in stones have been essential to human civilization.
Smoky Quartz is a grey and translucent variety of quartz. It ranges in clarity from almost complete transparency to a brownish-gray crystal that is almost opaque. Like other quartz gems, it is a silicon dioxide crystal. It was not commonly used in the ancient times, but it has recently become a popular gemstone used for jewelry.