Microcline, Lithian Muscovite (Lepidolite), Fluorcalciomicrolite

This is a mica specimen from the historic Harding Mine in northern New Mexico. While originally labeled as lepidolite (a now-discredited species), all pink mica from this mine has been identified as lithium-bearing muscovite, making its unusual coloration particularly interesting. The specimen also contains numerous grains of fluorcalciomicrolite—glassy, slightly translucent, yellow crystals named for their dominant fluorine and calcium content and their relationship to other microlite-group minerals.

The Harding Mine, discovered in 1900 and first worked in 1920, is a well-known Ta-Be-Li-Sn pegmatite locality. Owned by the University of New Mexico, collecting requires permission. This pegmatite was historically mined for "lepidolite", spodumene, beryl, and microlite. Its outer zone features quartz-microcline-muscovite-albite facies, while the inner zone hosts tantalum-lithium minerals, with cassiterite occurring as a minor accessory. The U.S. Bureau of Mines extensively drilled the deposit in the late 1930s and early 1940s. Specimens from this locality are rarely available on the market, making this an excellent sample for collectors of U.S. minerals or mica species.

--

This specimen comes from the collection of Dr. Peter Tarassoff, a prominent figure in mineralogy, particularly known for his work at Mont Saint-Hilaire (MSH). His diligent collecting and examination efforts have led him to be the first to identify at least 35 species and discover 12 new species, not only at MSH but also at other alkaline localities. Dubbed the "Dean" of Mont Saint-Hilaire collectors, Peter was honoured with the naming of the new species petarasite in 1980. He has authored or co-authored numerous mineralogical articles and has been a member of the Mineralogical Association of Canada since 1964. Additionally, Peter has volunteered at the Redpath Museum for the past 21 years, where he was formally appointed the Honorary Curator of Mineralogy. In recognition of his significant contributions to mineralogy, Peter was awarded the 2017 Pinch Medal.