Tunellite (Type Locality) on Ulexite (Kay Robertson Coll.)

Item Description

Tunellite is a very rare hydrated Sr-borate and the famous U.S. Borax Mine is the Type Locality. Three translucent, gray, doubly terminated prisms with satin lustre faces are aesthetically set on the front and back of the sculptural knobby ulexite matrix (so-called TV rock due to its interesting fiber optical properties). The impressive 1.7 cm crystal is on the front, with the back hosting two adjacent prisms, to 1.4 cm. Ex Kay Robertson Collection # 2149 and acquired as a gift in the early 1960s. Kay was a prominent California collector, who specialized in European classics (see the article in the March-April, 2007 Mineralogical Record and the 50+ page article in the German Magazine "Mineralien Welt" November-December 2017). A very showy and excellent combination of this rare species in a typical association. value ?