noun
Mineralogy term for the mineral dolomite (calcium magnesium carbonate).
白雲石はドロマイトとも呼ばれる鉱物です。
Hakuunseki is a mineral also called dolomite.
The exact derivation is uncertain; the kanji 白雲 (white cloud) and 石 (stone) are conventionally associated with the mineral dolomite.