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Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A mineral of silica-poor igneous, plutonic and volcanic rocks. Chemically, leucite is a potassium feldspar with insufficient silica to satisfy the chemical bonds. Because of the unfilled bonds, leucite weathers rapidly and can only be seen as inclusions in freshly broken rock. Full definition →
Etymology from Wiktionary, CC BY-SA 4.0.