SILEX achates. Calcedony or Agate. Location: Churchills, near Lanford, Somersetshire.Plate no. 514. From: Sowerby, James. 1802-1817. British Mineralogy: Or Coloured figures intended to elucidate the mineralogy of Great Britain. Plate from vol: 5. page no. 213.
All the coloured plates from Sowerby's British Mineralogy have been scanned and are available on Geoscenic.