This is a 73.9 Gram Naturally Tumbled Smokey Quartz Crystal was found in nature tumbled by the earth itself.
 
Smokey Quartz is a brown to black variety of Quartz that may appear to be smokey in lighter grey brown or light black varieties,  it gets its color from natural gamma irradiation also the inclusion of trace amounts of aluminum.
It has a hardness of 7 on the Mohs scale