Mineral
Fuller's earth
Picture to come.
A fine, absorbent clay dug from particular deposits, including in Surrey, Bedfordshire and near Bath. Fullers worked it into woollen cloth with water to draw out grease and dirt while the cloth was pounded and shrunk to thicken it. Fulling was done by trampling until water-powered fulling mills were introduced to England in the later 12th century.
Caveats (confidence: medium)
Which English deposits were worked in the 12th century is not documented in the sources opened.
Sources: en.wikipedia.org · en.wikipedia.org
Made by
- Dig clay