Danny Sanchez Opal seems to create a burst of blue flame in this Mexican rhyolite. Danny Sanchez Staining ... Gübelin in Photoatlas of Inclusions in Gemstones, Sanchez began teaching himself ...

One of the most fascinating is Rhyolite in the Bullfrog Hills, about 190km northwest of Las Vegas, near the eastern edge of Death Valley. This boomtown sprung to life after a couple of prospectors ...