A large group of aluminum silicate minerals that compose at least 60% of the earth's crust. Feldspars are divided into three primary groups:
3) calcium aluminum silicates - anorthite
Plagioclase feldspars contain sodium and calcium aluminum silicates while feldspathoids contain potassium and sodium aluminum silicates. A few of the feldspars are found as gemstones such as moonstone, sunstone, and Amazon stone, but most are found in mineral structures (granite, diorite). They are used the production of clays (kaolin), ceramics, glass, concrete, and abrasives. Feldspars act as a flux in ceramics, glazes, and glass by lowering the fusing point.
Synonyms and Related Terms
moonstone; sunstone; Amazone stone; granite; diorite; kaolin; feldspathic rock; feldespato (Esp.); feldspath (Fr.); feldspato (Port.); Feldspat (Deut.); veldspaat (Ned.)
|Mohs Hardness||6.0 - 6.5|
Hazards and Safety
No significant hazards from ingestion or skin contact. Inhalation may cause silicosis if stone contains free silica.
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