Igneous Rocks

andesite

Volcanic andesite (with crystals of hornblende) from the Lake District, 430 million years ago.

rhyolite

Rhyolite is fine grained, associated with silica-rich volcanoes, common in Snowdonia and Borrowdale.

granite

Granite cooled more slowly and has a coarser texture.

granite

In this specimen you can see slate being melting into a granite matrix.

For these drawings I’ve dipped back into my A-level geology notebook.