Basalt: rapid cooling in a lava flow produced individual crystals that are so small they are difficult to see with the unaided eye. Diabase: slower cooling in shallow intrusions such as sills, dikes, lopoliths or laccoliths allowed individual crystals to grow slightly larger - up to about two millimeters in size.

Is diabase the strongest rock?

The strongest rock in the world in compression is Diabase, which can stand up to 350 MPa. ... Close behind diabase in compressive strength come other fine-grained igneous rocks like Diorite, Gabbro, and Basalt.

What is the difference between basalt and diabase?

Diabase is actually a variety of gabbro which consists mainly of labradorite feldspar, augite, magnetite, and olivine. ... Basalt is identical to diabase and gabbro, but is very fine-grained. Basalt is from a melt that cooled very rapidly- in other words, on the surface of the earth or in the ocean.