Tag: kyanite

Geology of Gemstone Deposits

Large chlorite pseudomorph after garnet found in the Sierra Madre Mountains, Wyoming. The chlorite slowly replacedthe garnet and accepted the garnet’s crystal form.  Much of Wyoming is underlain by Archean cratonic basement rocks and cratonized Proterozoic rocks that provide favorable geological environments for a variety of gemstones – notably diamond, iolite, ruby, sapphire, garnet, kyanite,


A rockhound from Riverton mentioned opal south of town. The Cedar Ridge deposit lies along the highway & is cut by numerous oil field roads, no one had recognized that this place had one of the largest opal deposits on earth! A few old geological reports from 50 years ago briefly mentioned opal, so I


A 16-carat iolite from Palmer Canyon, Wyoming. I discovered iolite (water sapphire) at Palmer Canyon in 1995. The iolite occurred with gem-quality kyanite in mica schist & gneiss adjacent to vermiculite that had enough silica to form these gems. I couldn’t believe the amount, size & beauty of the stones. The single, largest, iolite gemstone


Ruby & Sapphire are beautiful stones. In 1995, I discovered my first ruby-sapphire-corundum deposit mixed with iolite & kyanite at Palmer Canyon west of Wheatland. After I recognized this association of gems with a rock type known as vermiculite, I started searching other vermiculites. It turns out that vermiculite is a alteration product known as