Rare Mineral Nicolayite: A Gem of Lead and Arsenic

Nicolayite is a rare mineral, with the chemical formula Pb3(AsO4)2. It is a lead arsenate mineral that was first described in 1859 and named after the French mineral collector and dealer, Nicolas-Theodore Nicollet (1790-1861). It crystallizes in the monoclinic system and typically forms tabular or prismatic crystals with a vitreous or pearly luster. The color of nicolayite can range from yellow to orange to red, depending on the presence of impurities.
Nicolayite is found in the oxidation zones of lead-bearing deposits, particularly in the type locality of the Saint-Benoît mine in the Vosges Mountains of France. It is also known from other locations in Europe, such as the Harz Mountains in Germany and the Tatra Mountains in Poland. In addition, nicolayite has been reported from a few deposits in North America, including the Franklin Mine in New Jersey and the Red Lake Mine in Ontario, Canada.
Nicolayite is considered a rare mineral and is highly sought after by collectors due to its distinctive color and crystal form. It is often found associated with other lead-bearing minerals, such as galena and anglesite, as well as with arsenate minerals like realgar and orpiment.