Hydroboracite (fine rare crystals) on Colemanite

Item Description

A fantastic and fine quality specimen of Hydroboracite from the Thompson Mine (Thompson Shaft) in Death Valley, California. This small cabinet sized piece features superb "tuft" or "fan"-like groups of white colored crystals of Hydroboracite on the top/display side of the specimen, associated with Colemanite on matrix. The largest crystal measures about 7 mm. Hydroboracite is not often seen in fine quality display specimens, and the pieces from the Thompson Mine are certainly some of the best examples that have been found.
From the collection of Robert (Bob) Reynolds (the number 630a can be seen on the underside of the piece from a previous collection). Bob was a well-known fossil and mineral expert and former Curator of Earth Sciences at the San Bernardino County Museum in California. The rare phyllomanganate-chromate species Reynoldsite was named in his honor in 2011.