. : :.i: I' r.\iU'N, Specific gravity usually greater than 2'5. With the exception of turquoise, silica is a prominent constituent of all these stones. Value usually not very great, only fine specimens of a few mem- bers of the group (cordierite, chrysolite, turquoise) have any considerable value. Specimens worth cutting of comparatively rare occurrence, others fairly frequent. Cordierite. Idocrase. Chrysolite. Axinite. Kvanite. 16. 17- 18. 19- 20. Staurolite. Andalusite. Chiastolite. Epidote. Turquoise. Where the Machines failed Fig. 3 shows a small mechanical washing plant in a rubber p
. : :.i: I' r.\iU'N, Specific gravity usually greater than 2'5. With the exception of turquoise, silica is a prominent constituent of all these stones. Value usually not very great, only fine specimens of a few mem- bers of the group (cordierite, chrysolite, turquoise) have any considerable value. Specimens worth cutting of comparatively rare occurrence, others fairly frequent. Cordierite. Idocrase. Chrysolite. Axinite. Kvanite. 16. 17- 18. 19- 20. Staurolite. Andalusite. Chiastolite. Epidote. Turquoise. Where the Machines failed Fig. 3 shows a small mechanical washing plant in a rubber plantationjn Ceylon. This was erected one or two good specimens (generally sapphires), J to I lb. of corundum crystals good enough for cheaper ornaments or for crushing down for cutting-powder, and the balance a mass of pretty glistening stones useful for cheap ornaments. It is a question why the'public prefer glass ornaments when they could get a real crystal from the residues of gem-washings. The cutting of gems is not such an expensive operation as most people think. A very few shillings will cut the stones of average size to be ready for mounting. Water-work As in all granite-formations, there is an abundance of water. This has been the prime power that has re-
Size: 2757px × 1813px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookleafnumber626, booksponsoruniversityofto, booksubjectscience
