tufa - large hand/display specimen from the paleoshoreline of ice age Lake Lahontan schist and gneiss in order

schist and gneiss in order of increasing metamorphosis

the ceramics designed to withstand very high temperatures in excess of 1

click to enlarge

from Way Too Cool that lets you see fluorescence in short

As described in 1925 by mining engineer Carl Millikan

tufa - large hand/display specimen from the paleoshoreline of ice age Lake Lahontan schist and gneiss in orderTufa is a calcium carbonate deposit that forms around the outlet of a hot spring that emerges below the surface of a body of water. These examples were formed during the Pleistocene high stand of Lake Lahontan, which filled a connected grouping of basins in Nevada east of Reno. It was similar to ice age Lake Bonneville in Utah, and now is greatly reduced in size. Its peak was approximately 12,700 years ago and its largest remnant is Pyramid Lake,