Diabase

Diabase (also known as dolerite or microgabbro^[1]) is an igneous rock that is often blue in colour. It is rich in magnesium and iron. Dikes and sills in igneous rock are often made of diabase.

Diabase

Diabase is mostly a silicate feldspar known as labradorite (about 40% to 70%). Most of the rest is pyroxene minerals (usually augite). Small amounts of hornblende, olivine, magnetite, and quartz are in some diabase rocks.