COMPOUNDS OF CALCIUM. 211 



gypsum in limestone. At Camillus and Manlius, N. Y., and 

 in Davidson County, Tenn., are other localities. Fine crys- 

 tals of the form represented in figure 5 come from Poland 

 and Canfield, Ohio, and large groups of crystals from St. 

 Mary's in Maryland. Troy, X. Y., also affords crystals in 

 clay. In Mammoth Cave, Kentucky, alabaster occurs in 

 imitation of flowers, leaves, shrubbery, and vines. Alabas- 

 ter is obtained at Castelino in Italy, 35 miles from Leghorn. 

 Massive gypsum occurs abundantly in New York, from 

 Syracuse westward to the western extremity of Genesee 

 County, accompanying the rocks which afford the brine 

 springs ; also in New Brunswick, especially at Iiillsboro', 

 where part is excellent alabaster ; in Hants, Colchester, and 

 other districts in Nova Scotia ; also in Ohio, Illinois, Vir- 

 ginia, Tennessee, Arkansas, and Nova Scotia; and in con- 

 nection with the Triassic beds of the Rocky Mountain 

 region; also abundant in Nevada and California. It is 

 abundant also in Europe. 



Gypsum, when calcined, loses its water, becomes white, 

 is easily ground to a powder. This powder, when mixed 

 with a little water, takes up water again and becomes hard 

 and compact. This gypsum is plaster of Paris, and is used 

 for taking casts, making models, and for giving a hard finish 

 to walls. Alabaster is cut into vases and various ornaments, 

 statues, etc. It owes its beauty for this purpose to its snowy 

 whiteness, translucency, and fine texture. Moreover, owing 

 to its softness, it can be cut or carved with common cutting 

 instruments. Gypsum is ground up and used for improving 

 soils. 



Anhydrite. — Anhydrous Calcium Sulphate. 



Trimetric. In rectangular and rhombic prisms, cleaving 

 easily in three directions, and readily breaking into square 

 blocks. /A/=100°30'; HaH=85° and 1 



95°. Occurs also fibrous and lamellar, often 

 contorted ; also coarse and fine granular, 

 and compact. 



Color white, or tinged with gray, red, or 

 blue. Lustre more or less pearly. Trans- 

 parent to subtranslucent. H. = 3-3'5. G. 

 = 2-0-3. 



Composition. Ca 4 S = Sulphur trioxide 

 58*8, lime 41-2 — 100. It is an anhydrous 

 calcium sulphate. B.B. and with acids, 



y 





2. 



V If*. / 



r>- 



—n=?f 



/ l) 





3. 



<v 



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