Igneous rocks contain few or no combustible elements. And it’s very hard to remelt them back into magma because they ...

Igneous rocks close igneous rockIgneous rocks are ... to weathering and erosion and are therefore very hard-wearing. Examples of metamorphic rocks include marble, which originates from limestone ...

Extrusive igneous rocks are formed by magma that has erupted onto the surface as lava and then cooled quickly. Obsidian is an example of an extrusive igneous rock. Obsidian has crystals which are ...

Igneous rock is formed by the cooling of molten rock ... which generally destroys any fossils that were in the rock before it was metamorphosed. For example, marble is created when limestone is ...

The rock was excavated from the Bushveld Igneous Complex in South Africa, an area known for its rich ore deposits. This is the oldest example of living microbes being found within ancient rock so ...