青あお石いし

noun

bluish stone; greenish stone

General term for a stone with a blue or green tint. Can refer to various types of rock or decorative stone.

• 庭にわに青あお石いしを敷しき詰つめた。

  We paved the garden with bluish stones.

noun

blue-tinged tuff

Specifically refers to a type of tuff (凝灰岩) with a bluish color. A more technical or geological usage.

See also: 凝灰岩

• この地ち域いきでは青あお石いしと呼よばれる凝ぎょう灰かい岩がんが採とれる。

  In this region, a tuff called 'blue-tinged tuff' is quarried.