Alum shale quarry. Historical artwork of an alum shale quarry on the Yorkshire coast, UK. Alum is the double sulphate of aluminium and either potassium or ammonia. It is used as a fixative in the dying and tanning industries, in cosmetics and as a preservative in food preparation. Alum was quarried in Yorkshire from the early 17th Century until around 1870. Image by Robert Havell from 'The costume of Yorkshire', by George Walker (1814).