Opal from Camborne, Cornwall, England, UK
UK | |
| Collins, J. H. (1871) A Handbook to the Mineralogy of Cornwall and Devon. Heard and Sons, Truro. Hall, T.M. (1868): Edward Stanford (London), 168 pp. |
| Phillips, William (1823) An Elementary Introduction to Mineralogy (3rd ed.) |
| Phillips, William (1823) An Elementary Introduction to Mineralogy (3rd ed.) |