Among the fossils found at The Naze, in Walton, are numerous objects resembling wood, which in fact are iron pyrites, used 300 years ago.

Because of its special geology Walton was one of the chief places for the production of copperas or green vitriol, a ferrous sulphate, which was used for a variety of purposes including inks and dyes.

The copperas was manufactured from pyrites, abisulphide of iron washed out of the London clay at Walton’s Naze onto the shore.

There the raw material was collected by copperas pickers - the wives and children of fishermen and other poor people, who were in exchange paid in tokens. Some copperas stones were also dredged up from the sea floor by boats.

The material was then taken to a copperas house to be chemically transformed into the green vitriol.

It is yet unknown when copperas production was established at Walton, but it was probably in the 17th century.

A detailed inventory of the copperas house from 1702 indicates, the house had a boiler and several coolers, a great variety of tools and equipment and much old scrap iron.

The factory was located between Mill Lane and Vicarage Lane, close to Walton Channel, the Tidal Mill and wharves there, a water supply being important for both the manufacturing process and for the export of the final product.

The production was quite interesting, as the copperas was first packed into heaps, mixed with scrap-iron and then moistened.

The solution was then removed to leaden tanks or boilers where heat concentrated the product. This was later gathered and packed into barrels.

The raw copperas found on the shore were usually owned by the Lord of the Manor from whom the copperas manufacturers took a lease to allow them to collect it.

In 1772 the Lord of the Manor of Walton, the Rt Hon William Henry, Earl of Rochford, of St Osyth Priory, leased the rights to Ephraim Rinhold Seckl for 21 years.

Although production at Walton ceased sometime in the earlier 19th century, the raw material continued to be collected there until the late 19th century, which was later on transported to chemical factories in London and Ipswich.