[20 



SALTS OF LIME. 





/The mineral is subjected to the action of sulphuric acid , the 

 sulphate of lime being insoluble is deposited, leaving the sul- 

 phate of magnesia in solution. A more economical method 

 I is to boil the calcined stone in proper proportions in bittern , 

 { the muriatic acid of the bittern takes up the lime. 



Ankerite. This species resembles brown spar, and like that becomea 

 brown on exposure/ The primary is a rhombohedron of 106° 12'. It 

 consists of the cajtoonates of lime, magnesia, iron t arid manganese. The 

 Styrian iron ore' beds and Saltzburg are some of its foreign localities. 

 Tt is said to o/eur in veins at Quebec and at West Springfield, Mass. 



7, apatite . — Phosphate of Lime, 



In hexagonal prisms. The annexed figure represents a 

 yO^^v cl T s ^ a ^ from St. Lawrence county, New York. 

 I V \ ^\ Cleavage imperfect. 



Usually occurs in crystals ; but occasionally 

 massive ; sometimes mammillary with a compact 

 fibrous structure. Small crystals are occasionally 

 transparent and colorless, but the usual color is 

 . green, often yellowish-green, bluish-green, and grayish-green ; 

 sometimes yellow, blue, reddish or brownish. Coarse crys- 

 tals nearly opaque. Luster resinous, or a little oily. H=5. 

 Gr=3 — 3*25. Brittle. Some varieties phosphoresce when 

 heated, and some become electric by friction. 



Composition: phosphate of lime 92*1, fluorid of calcium 

 7*0, chlorid of calcium 0*9. Infusible before the blowpipe 

 except on the edges. Dissolves slowly in nitric acid without 

 effervescence. Its constituents are contained in the bones 

 and ligaments of animals, and the mineral has probably been 

 derived in many cases from animal fossils.* 



Asparagus stone is a translucent wine-yellow variety oc- 

 curring in talc at Zillerthal in the Tyrol. Phosphorite is a 

 massive variety from Estremadura in Spain, and Schlacken- 

 wald in Bohemia. Moroxite is a greenish-blue variety from 

 Arendal. Eupyrchroite (Emmons) is a fibrous mammillary 

 variety from Crown Point, Essex county, N. Y. 



What is the common form of apatite ? is colcrs and appearance? la 

 it harder than calc spar? What is the principal constituent in its com- 

 position ? What is a probable origin of this mineral in many cases ? 



* Bones contain 55 per cent, of phosphate of lime, with some fluorid 

 of calcium, 3 to 12 per cent, of carbonate of iime, some phosphate of 

 magnesia and chlorid of sodium, besides 33 per cent, of animal matter. 



