ROCKS AND MINERALS OF CEYLON. 



45 



zircon, are treated in a similar manner. A good test for a 

 sapphire is, that in a dark room or closet, with the light of a 

 match or candle, it should appear equally rich in color as in 

 ordinary light. Sapphires are lamellar in structure, and so, on 

 being cut of a convex form, we have the appearance of a six- 

 rayed star. 



Spinel. Another mineral abundant in Ceylon crystallizes 

 in the cubic system generally in octohedrons or rhombic dode- 

 cahedrons. In color this mineral varies much ; red, however, 

 is very common, and it is sometimes sold as ruby. The specific 

 gravity of spinel is about 3*5, while ruby is 4 and garnet 3-8. 



Green spinel is occasionally met with at Ratnapura and in 

 the Kandy district. 



Garnet, of various kinds, is found in Ceylon both in the 

 metamorphic rock as well as in the alluvium. This is usually 

 of a red color, and crystallizes in the cubic system. 



Cinnamon stone (essom'te) is a kind of garnet found 

 largely at Matara. 



Zircon crystallizes in the tetragonal system, and is found 

 of many colours. (Several varieties are disregarded by the 

 Sinhalese ; others are used, notably the white zircon, otherwise 

 known as the Matara diamond. Quartz is often cut and sold 

 as Matara diamond. 



Chrysoberyl belongs to the rhombic system of crystals, and 

 when cut encabochon furnishes the true cat's-eye. 



Tourmaline (S Toramalli) crystallizes in the hexagonal 

 system, generally in prisms with dissimilar ends. In color it 

 varies much ; thus, we have black, green, brown, yellow, &c. 



The Peridot of Ceylon is yellow tourmaline. The natural 

 crystals shew a fine striation on their long sides. 



Moonstone or adularia is a felspar with a pearly appear- 

 ance. Quartz and selenite are often sold under the same name. 



Rock Crystal crystallizing in the same system as the 



