Type of igneous rock formed deep in the earth's mantle that extrudes as pipes. Kimberlites are well known as the source rock that produces Diamonds.

Assuming the shape of a pseudo-octahedron.

Area in the earth's crust where hot gases or lava escape.

A wall of igneous rock that cuts across layers of surrounding rock.

Abbreviation of Karat

Crystal shape that is very similar to an octahedron, but is not a true octahedron as it lacks the symmetry.

The escaping of hot gases or lava from the crust of the earth.

Describing two minerals that are dimorphous to one another.

Short for Laboratory

1) Rhombohedron shaped crystal that is almost identical to a cube, but its angles slightly differ from a cube. 2) Any crystal that closely resembles a member of the isometric crystal system but is sli [..]