Igneous rock is formed through the cooling and solidification of magma or lava. Igneous rock may form with or without crystallization either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks. Igneous and Metamorphic rocks make up 90?95% of the top 16 km of the Earth’s crust by volume.

Contains 5 types of Igneous rocks:
1 each of Basalt Granite Obsidian Pumice and Cinder

Great set to learn about rock identification.

Intended to be parts for use with science projects science fairs etc. and are provided with minimal to no operating instructions.