Riebeckite
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Riebeckite is a sodium-rich member of the amphibole group of silicate minerals, chemical formula Na2Si8O222. It forms a solid solution series with magnesioriebeckite. It crystallizes in the monoclinic
Black riebeckite in an alkaline pegmatite from Lindinosa near Évisa, Corsica, France
Crocidolite, variety of riebeckite, from Pomfret Mine, Vryburg, South Africa
Silicate mineral
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Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust.
Lithium aluminium silicate mineral spodumene
Diatomaceous earth, a biogenic form of silica as viewed under a microscope. The imaged region measures approximately 1.13 by 0.69 mm.
Nesosilicate specimens at the Museum of Geology in South Dakota
Kyanite crystals (unknown scale)