LIME. 



213 



Saratoga County. In the town of Greenfield, a mile from the springs, apatite has been 

 found in reddish brown crystals an inch or more in length, in a vein of granite, associated 

 with chrysoberyl, tourmaline and garnet.* 



Westchester CoUxNty. Apatite, in low six-sided ]jrisms truncated on the terminal edges 

 (Fig. 113), has been found at Anthony's Nose. These crystals arc of a brownish or yellow- 

 ish green colour, and vary from half a line to an inch in length. They are either perfect or 

 liave their angles rounded, azid generally present two faces broader than the other four. This 

 locality is believed to have been first noticed by Dr. G. Troost.f 



This mineral also occurs at Yonkers and West-Farms, where it is associated with tourma- 

 line and garnet ; but no very good specimens liave yet been obtained at these localities. 



FLUOR SPAR. 



Cliaux Fluatee. Hauy. — Fluate of Lime. Claivcland. — Fluor Spar. Phillips and Thrnnsm,. — Octahedral 

 Fluor. Jaiiuson. — Octacdrisches Flus-Haloid. Mohs. — Fluor. Kirwiii and SAcparil. — Fluorine. Bcudont. 



Fig. 111. 



Fig. 115. 



Description. Sometimes transparent and 

 colourless ; but more frequently white, grey, 

 black, blue, green, yellow, red or brown. It 

 crystallizes in cubes, which are cleavable into 

 octahedrons and regular tetrahedrons. Fig. 114. 

 The primary form is the regular octahedron. 

 Fig. 115. It also occurs massive and disse- 

 minated, nodular and earthy. Lustre vitreous. 

 Varies from translucent to transparent. Brit- 

 tle and easily frangible. Hardness 4.0. Spe- 

 cific gravity from .3.10 to 3.20. Before the blowpipe, it decrepitates, and at length fuses 

 into an opaque enamel. It is attacked by acids. 



When fluor spar is acted on by sulphuric acid, it evolves a gas which corrodes glass ; and 

 it may thus be distinguished from calcareous spar. It is also harder than the latter mineral. 



Composition. According to the researches of the most able chemists, this mineral, in its 

 pure form, is composed of fluorine 48. 13, and calcium 51 .87 ; but is most commonly mi.xed 

 with silica and other foreign substances. Its formula is CaF. 



Geological Situation. It occurs in veins and beds in gneiss, mica slate and clay slate, 

 in various metalliferous formations of cobalt, silver, tin, lead, copper, etc.; less frequently in 

 transition rocks and very abundantly in some secondary rocks, as limestone. In New-York, 

 it is found in series of calcareous spar, in gneiss and in various calcareous limestones. 



» Shepard. Treatise on Mineralogy, 1835. f Manoirs of the Academy of Natural Sciences of Philadelphia. II. 55. 



