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Exhibit of the Month 12 / 2017
Cinvaldit (lithian mica, zinnwaldite)
Cinvaldit is today a group name for dark micas containing lithium. It is no longer considered a separate mineral species. This group of micas is often found in tin-tungsten ore deposits. In the Czech Republic, the most significant deposit is Cínovec in the Teplice district. Another industrially exploitable deposit is the area of Horní Slavkov in the Sokolov district. Other occurrences in the Czech Republic are not extensive enough to be utilized for lithium raw material extraction. They are only mineralogically interesting localities – Krupka in the Teplice district, Puklice and Jeclov in the Jihlava district, Nová Ves near Křemže in the Český Krumlov district, Boží Dar and Vykmanov in the Karlovy Vary district.
Cinvaldit most commonly occurs at Cínovec as veins reaching decimeter thickness, in the form of flaky aggregates, or in the cavities of quartz veins as neat tabular crystals.
At the Cínovec deposit, tin ore was primarily mined since the 14th century, and from the second half of the 19th century, wolframite was also mined. The richest ore of tungsten began to be used in metallurgy for the production of high-quality steels.
Until the end of the 1990s, tin-tungsten ore was mined at the Cínovec deposit. Lithium from the ore was essentially waste and ended up in the tailings. The reason was very simple; there was almost no application for lithium at that time. It was only the boom of mobile technologies at the end of the last century that led to increased interest in lithium. To a small extent, lithium is also used in nuclear energy, chemical, glass, and ceramic industries. Currently, Bolivia has the largest lithium reserves, where half of the known lithium reserves on Earth are stored in salt flats. Our location, Cínovec, contains about 1.3 million tons of lithium. This makes Cínovec the largest lithium deposit in Europe.