Copperas works

Period: 16th century

Copperas (green vitriol, iron sulphate) was used in dyeing, ink and tanning. It was not made in 12th-century England. Manufacture began in the late 16th century: patents were granted in 1562 and 1565, and works were established at Queenborough, Whitstable and Deptford in Kent. Iron pyrites gathered from the shore was left to weather in long clay-lined beds, and the liquor was boiled in lead-lined pans.

Sources: kentarchaeology.org.uk