Muscovite pseudmorph after Beryl (rare locality)

Item Description

The area around Ardeth Lake in the Sawtooth Mountains of Idaho has produced some of the richest blue colored crystals of Beryl in the world. They're almost too dark to be called Aquamarine, and I've heard some people say that they should be called "Blue Beryl", because the hue is much deeper than the actual definition of Aquamarine. I've seen similarly colored crystals from Erongo Namibia, and Xuan Le, Vietnam, but the Idaho specimens are highly sought after as they are incredibly scarce on the market. This piece is a notably rare pseudomorph from this area featuring silvery Muscovite Mica which has replaced a prismatic, hexagonal crystal of Beryl, sitting on cream colored Feldspar matrix. It's honestly the ONLY piece of the material that I can remember seeing from Idaho. The pseudomorph measures 2.7 cm long, and is complete all around. If you collect pegmatite minerals, pseudomorphs or specimens from the Sawtooth Mountains, this is something rare and unique that I'll bet you don't have in you collection, so don't miss out. Valued $1,250.
From the collection of William ("Bill") (1927-2006) and Anne (1928-2021) Cook of Cleveland, Ohio (#7857) with a label from Tom Loomis. This husband and wife duo were actively involved in the mineral world for many decades. Bill was a PhD geologist, and Anne was a mathematician, and they both were very serious mineral collectors. Bill served for many years as adjunct curator of mineralogy at the Cleveland Museum of Natural History, and Anne was inducted into the Micromounters' Hall of Fame on October 12, 2019. Both Bill and Anne, at various times, served as president both of the Mineralogical Society of Cleveland and of the Micromineral Society of the Cleveland Museum of Natural History. The rare barium lithium beryllium phosphate Wilancookite was named in their honor in 2015.