LIME. 239 



Composition. Sulphuric acid 58.00, lime 41.70, water 0.7, silica 0.09 {Stromeyer). 

 The two last, howcTer, are accidental ingredients. It also sometimes contains a minute pro- 

 portion of common salt. Formula CaO.SOj. 



Geological Situation. This mineral is found massive and in beds in the salt and secon- 

 dary gypsum formations. It is frequently intermixed with rock salt, also with stinkstone, 

 sahniferous clay, and occasionally with ores of different kinds. Some varieties are met with 

 in transition and primitive rocks. The former is its situation in the State of New-York. 

 Several of the varieties are found in the red sandstones of England and Scotland. 



LOCALITIES. 



Niagara County. At Lockport, this mineral occurs foliated, transparent or translucent, 

 and of a blue colour, in geodes in the limestone. The decomposed mineral, epigene of Haiiy, 

 also occurs at the same locality, in thin coatings upon the foliated variety, and also filling up 

 crevices of the folia. From the foliated mineral, the primary form can be obtained by clea- 

 vage. It is often mixed with carbonate of lime, so that fragments thrown into an acid, effer- 

 vesce. Sometimes, also, it contains a considerable proportion of water, although its crystalline 

 arrangement is unaffected. It is not easy to determine to what extent this change has taken 

 place, and how far the masses of common gypsum found at Lockport may have resulted from 

 causes which have operated subsequently to the original deposition. 



With the exception of the preceding, I know of no other locality of anhydrite in this State. 

 The minute crystals found at the Sharon springs in Schoharie county, have often passed 

 by this name among our mineralogists, but those that I have seen belong to the preceding 

 species. 



APATITE. 



[From WKOLTCM, to deceive ; from its being easily mistaken for other minerals.] 



Chaux Phosphatee. Haiiy. — Phosphate of Lime. Ckavckmd. — Rhombohedral Apatite. Jameson. — Rhom- 

 boedrisches Flus-Haloid. Molis. — Subsesquiphosphate of Lime. Thomson. — Apatite. Phillips, Beudant, 

 Shepard and Dana. 



Description. Colour white, green, blue, red, yellow and brown ; 

 usually dull. It occurs regularly crystallized; also massive and dis- 

 seminated. The primary form is a regular six-sided prism. Fig. 106. 

 M on M 120°. Cleavage parallel with the sides and base of the 

 primary, but difficult. Fracture conchoidal and uneven. Lustre resi- 

 nous, and varying from splendent to glimmering. Alternates from 

 transparent to feebly translucent on the edges. Brittle and easily 

 frangible. Hardness 5.0. Specific gravity from 3.00 to 3.30. Be- 

 fore the blowpipe, it is very difficultly fusible. With borax or biphos- 

 phate of soda, it melts easily into a glass. It fuses also when mixed 

 with carbonate of iron. It is dissolved in nitric and muriatic acids, 

 and the solution is abundantly precipitated by oxalate of ammonia. 



Fig. 106. 



m: 



M 



