Photographic feature: Gypsum crystal mineralogy

Gypsum Crystal Mineralogy

This photographic article considers the habit and mineralogy of gypsum crystals from a glacial till deposit and Jurassic rock strata in Northamptonshire (UK). The crystals display excellent examples of fish-tail and swallow-tail twinning as well as unusual features such as deformed twin planes, clay inclusions and ripple-like textures.

Gypsum in the Oadby Member Glacial Till

General features

Coarse selenite (prismatic/well-formed gypsum) crystals, up to 100mm in length, are present within the Oadby Member glacial till exposed within a quarry local to the Weldon area of Northamptonshire, UK. Gypsum crystals from this area range in size from 5mm to 150mm (typically 30-50mm) and are generally colourless to light grey.… Read the rest