Berthierite (iridescent crystals)

Item Description

Here we have a beautiful old-time Berthierite specimen from one of the great old European localities. This piece is from the classic Baia Sprie Mine (Felsobanya Mine) in Romania and features dozens of acicular, silvery-grey needles of Berthierite with a notably eye-catching iridescence on the surface, surrounded by white trigonal crystals of Calcite on matrix. A wonderful example of this rare and classic material from a locality that was mined continuously from the 14th century until 2006. PLEASE NOTE: This specimen was originally and erroneously labeled as Stibnite, which was a common mistake back in the day for this material, as it is chemically similar to Berthierite. For reference, Berthierite is a rare iron antimony sulfosalt and not often found in good crystallized specimens. In 1827 the species was named after Pierre Berthier a chemist from France, and mineralogist at the Ecole des Mines. From the worldwide mineral collection of Albert Lewis Kidwell (January 1, 1919 - August 16, 2008). Al was a well-known mineral collector and research geologist with Carter Oil Company and later Exxon Oil Company in Houston, Texas. The phosphate species Kidwellite was named in his honor in 1974 ( https://www.mindat.org/photo-326405.html ).