Permian Corrie Sandstone (Hunterian Museum, rock number TS20844)

This is from the "new" pier, cut into the Permian south of Corrie village. It consists mainly of quartz in this view, although grains of alkali feldspar, and lithic fragments also occur. All the grains tend to be highly rounded, and most have a reddish brown coating of hematite.

Between crossed polars, (shown above) the quartz shows typical low order birefringence colours. The central round grain shows nice quartz cement overgrowths. There are also diagenetic clay minerals showing higher order colours, as isolated flakes, and as overgrowths (eg on the grain at the top left). The pore space in the rock is isotropic.