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

NCE: Thaumasite damage to M5 bridge foundations

Thaumasite Damage to M5 Bridge Foundation Concrete

This month’s issue of New Civil Engineer (May 2016), the magazine of the Institution of Civil Engineers, features the long-term remedial works to the concrete foundations of overbridges along the M5 in southern England, UK, as a result of thaumasite damage.

In the article, titled “Concrete Concern – Long term rescue effort underway for M5 bridges with crumbling foundations”, Dave Parker (of NCE) discusses the background to the UK thaumasite problem, the extent of damaged bridges and the on-going remedial programme. The full article can be found on the NCE website by clicking here.… Read the rest