- feldspar (n.)
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- type of mineral common in crystalline rocks, 1785, earlier feldspath (1757), from older German Feldspath (Modern German Feldspat), from Feld "field" (see field (n.)) + spath "spar, non-metallic mineral, gypsum" (see spar (n.2)); spelling influenced by English spar "mineral." Related: Feldspathic.