Muscovite ps. Andalusite (rare !) ex Kay Robertson

Item Description

Interesting, and unusual, this rare replacement pseudomorph is from Clark Valley in California. The Andalusite, an aluminum silicate, has been replaced by Muscovite, creating a long, slender pseudo with a varied, pearly luster. The pseudo is 5.1 cm long, and exceptional for what it is and this is actually the only specimen of this rare and highly interesting replacement we have ever had (twice, as we sold it to Bob from Kay's collection a few years ago). Formerly in the well-known Kay Robertson collection. 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). This was recently deaccessed from the extensive collection of Bob Reynolds, who cherished both minerals and fossils as he collected. Bob is a prolific author and has had several curating positions in museums.