Topaz, is a silicate mineral made of aluminum and fluorine.  It is used as a gemstone in jewelry and other adornments.  Common topaz in its natural state is colorless, though trace element impurities can make it pale blue or golden brown to yellow-orange, this particular "brown" looking topaz is referred to as "sherry topaz" named after sherry wine. 
 
Unfortunately, through exposure to UV, this sample will eventually lose all color and become clear.  There are irradiation process to set the color of the stone, but this one is natural.  

Topaz is one of the hardest naturally occurring minerals with a hardness of 8, just behind Corundum (ruby) at 9, and Diamond at 10. 

I surface mined this specimen in the Thomas mountain range in Utah.  Large chunks of rhyolite were blasted out using explosives, then the minerals were collected by hand using hammer and chisel to finish breaking up the host rock.