脈みゃく石せき

noun

gangue; veinstone

Technical term in mining and geology for the non-valuable mineral material surrounding ore in a vein.

See also: 鉱石

• 鉱こう石せきから脈みゃく石せきを取とり除のぞく工こう程ていが必ひつ要ようだ。

  A process to remove gangue from the ore is necessary.