noun
A dark-colored igneous rock, also known as dolerite. Used in geology.
輝緑岩は玄武岩に似た火成岩である。
Diabase is an igneous rock similar to basalt.
From 輝 (ki, 'shine') + 緑 (ryoku, 'green') + 岩 (gan, 'rock'), referring to the rock's often greenish, shiny appearance. The exact historical derivation is uncertain.