Igneous rock

Igneous rock was a geological classification referring to rock formed quickly by the solidification of lava from erupting volcanoes or other significant geological events. While other forms of rock are generally formed by millions of years of pressure inside a planet, Igneous rock was generally not. One type of igneous rock was granite.

Diamagnetic minerals could be found in igneous rock. Commander Trip Tucker noted this to Zho'Kaan when trapped on a planet with the Arkonian in 2152. 

A red rock discovered by the crew of the USS Enterprise (NCC-1701) on the Kalandan outpost planet in 2268 looked like igneous rock, but was significantly denser.