DOLERITE - Trusham Quarry, Devon

Coarse-grained dolerite showing feldspar crystals together with chlorite, pyroxene and epidote. The weathering of the feldspar and chlorite has imparted a brown colouration.

This specimen is from a dolerite sill, over 65 metres thick, exposed in the quarry. The sill has been injected at a very high temperature into the Lower Carboniferous shales, which has baked the adjacent shale, converting it into slate, a metamorphic rock.

A nice example. Collected in 1998.