Orthoclase pseudomorph after Ernstite with Goyazite (rare)

Item Description

A really interesting and unusual pseudomorph / ''cast'' specimen from Linopolis, Brazil featuring cream colored bladed crystals of Orthoclase (the label refers to it as var: Adularia) which have completely replaced a crystal of Ernstite, which is essentially a oxidized / altered mineral that forms from Eosphorite. So in essence, this specimen started out as Eosphorite, later oxidized and altered into Ernstite, and then was replaced by Orthoclase into its current state. Additionally, small golden-brown crystalline areas of Goyazite can be seen for a nice touch. You can see the sword-shaped prismatic habit of the original Eosphorite/Ernstite crystal is incredibly well-preserved, and if you flip the piece over, you'll see it's partially concave, and is more of a thin crust than a full crystal replacement. Very interesting and unique and certainly hard to find on the market. This is the first piece of this material that we've ever had to offer in the auctions. From the collection of William ("Bill") (1927-2006) and Anne (1928-2021) Cook of Cleveland, Ohio (#9261). 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, and Anne was inducted into the mi The rare barium lithium beryllium phosphate Wilancookite was named in their honor in 2015.