Geology Site Account

Site name: Copperas Bay and Copperas Wood

Grid reference: TM 199312 (entrance to the reserve)

Summary of geological interest

Site of historical interest only. The copperas industry is commemorated in the name of Copperas Wood and Copperas Bay. Copperas Wood is an Essex Wildlife Trust reserve and also a biological SSSI. Grid reference is the entrance to the reserve.

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Site description

The copperas industry was an important industry in eighteenth century Essex. It involved gathering of pyrite nodules (known as copperas stones) from beaches, where they had been washed out of the London Clay, and then allowing them to oxidise for several months in open vats. This lengthy and hazardous industrial process converted the nodules to ferrous sulphate (green vitriol), which was an essential chemical for making dyes, ink, and several industrial chemicals such as sulphuric acid. Women and children were employed to gather the nodules from the beaches and were paid in copperas tokens.

A copperas works is marked as Copperas House on the 1882 geological map (based on an 1838 original plate) and the exact site may have been where Copperas Wood Farm now is (TM 204 318).