Translation guide
A type of dark-colored igneous rock, known as 輝緑岩 (きりょくがん) in Japanese. This is a technical geological term.
Referring to the specific igneous rock diabase (also called dolerite).
Diabase is a specialized geological term. In everyday conversation, it is rarely used. If you need to refer to a dark, hard rock in a non-technical context, you might use a more general term like 黒っぽい硬い岩 (くろっぽいかたいいわ).
ドレライトは玄武岩と似た組成を持つ。
Dolerite has a composition similar to basalt.