Cryolite with Siderite

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Rich masses of cryolite with minor siderite. Classic material for this locality.Ivigtut, located on the Arsuk Fjord in southwest Greenland, is world-famous as the only place on Earth where cryolite was ever found in commercial quantities. Geologically, the deposit consisted of a massive, pegmatitic body of nearly pure cryolite hosted within a peralkaline granite stock that intruded Precambrian gneisses. This unique mineralogy formed approximately 1.2 billion years ago, resulting in a dense pocket of sodium aluminum fluoride often associated with siderite, quartz, and various rare halides. Historically, mining and quarrying at Ivigtut began in 1854 after the minerals utility as a flux in the aluminum smelting process was discovered. The mine operated as a deep open-pit quarry for over 130 years, proving vital during World War II when it provided the necessary cryolite for Allied aircraft production. While the primary ore body was exhausted and commercial mining operations officially ceased in 1987, the site remains a legendary mineralogical locality for researchers and collectors.