
Igneous Rocks
Igneous rocks are formed from molten rock called magma. They are mostly crystalline (made up of interlocking crystals) and usually very hard to break.
Basalt

Pumice

Gabbro

Barry Marsh, School of Ocean and Earth Science, University of Southampton
Gabbro is made of coarse-grained (5mm or so) interlocking crystals. Its overall colour is dark grey but it often contains glassy or pale-coloured crystals of feldspar as well as dark minerals.Granite

Barry Marsh, School of Ocean and Earth Science, University of Southampton
Granite is made of coarse-grained (5mm or so) interlocking crystals. It has more light coloured crystals than dark, usually of white or pink feldspar, glassy quartz, and shiny mica.