Fluorite on Quartz replacing Calcite

Item Description

A really interesting display specimen from the old Erika Mine featuring a coverage of textbook, razor-sharp, well-formed cubes of gemmy colorless Fluorite which are coated with reddish-brown iron oxide sitting atop a "cast" drusy white Quartz which has replaced a scalenohedral crystal of Calcite on the underside. If you look on the bottom of the piece, you can see the negative cavity where the Calcite once grew, and was later completely dissolved and replaced by Quartz. The largest Fluorite crystal measures 7 mm on edge, and upon close inspection you can see that some of the crystal faces are not coated with the iron oxide creating a very attractive two-tone effect. A great example of this hard to find material from this old locality in southeastern Germany just west of Nabburg. Ex Kay Robertson Collection (#4751). Kay was a prominent California collector, who specialized in European classics. She nearly lived 100 years from April 1920 - March 2020. See the article in the March-April, 2007 Mineralogical Record ( https://www.mineralogicalrecor... ), and the 50+ page article in the German Magazine "Mineralien Welt" November-December 2017.