Basalt thin section slide exhibiting the fine grained, mafic nature of this extrusive igneous rock. Fine laths of plagioclase contrast beautifully against the bright coloured clinopyroxene making for an attractive thin section. Basalt is one of the most common rocks, and an important one for students. It's a fine grain rock with a crystalline structure and typically black in colour due to the abundance of iron within the rock. Basalt forms when mafic magma cools quickly near the surface of the planet hence the small crystal texture. This particular material comes from Scotland and dates back to the Tertiary period. Each section is made to 30 microns thickness and the glass is 46 x 27 mm in size with a cover slip. Supplied in a protective card sleeve with a label, ideal for microscopy and educational purposes.