Pargasite / Hornblende (?) (Amphibole) (ex Kay Robertson and Collection)

Item Description

Please note that this piece was labeled orginally as "Hornblende (Pargasite)" (see the old handwritten attached label on the front of the specimen). I'm not 100% certain which species it could be, and without analysis, it's best left as being labeled a member of the Amphibole Group. I've never seen a confirmed piece of Pargasite from Tilly Foster, but I have seen specimens of "Hornblende" (Ferro-hornblende and Magnesio-hornblende). With that said, this is a remarkably fine quality specimen for the locality as is features SHARP and LUSTROUS, dark greenish-black, monoclinic crystals that measure up to 1.3 cm in greyish Calcite and massive Amphibole matrix. The most important aspect of the piece is the fact that the Amphibole crystals are ISOLATED and not tightly intergrown. They are distinct, and completely separated, so you can distinguish one from another, which is almost never seen for the material. I value this one at $1,500 for the quality, aesthetics and the fact that it's from the famous Tilly Foster Mine. Ex Kay Robertson Collection (#466). Kay is 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).