FLUOR SPAR 



121 



Dif. Distinguished by its inferior hardness frorr beryl, it 

 being easily scratched with a knife ; by dissolving m acids 

 without effervescence from carbonate of lime and other car- 

 bonates ; by its difficult fusibility, and giving no metallic 

 reaction before the blowpipe from phosphate of lead and 

 other metallic species. Its phosphorescence is also an im- 

 portant characteristic. 



Obs. Apatite occurs in gneiss and mica slate, granular 

 limestone, and occasionally in ancient volcanic rocks. The 

 finest localities in the United States occur in granular lime- 

 stone. The crystals from the limestone of St. Lawrence 

 county, N. Y., are among the largest yet discovered in any 

 part of the world. One from Robinson's farm measured a 

 foot in length and weighed 18 pounds. But they are nearly 

 opaque and the edges are usually rounded. They occur with 

 scapolite, sphene, &c. Edenville and Amity, Orange county, 

 N. Y., afford fine crystals from half an inch to twelve inches 

 long. At Westmoreland, N. H., fine crystals are obtained in 

 a vein of feldspar and quartz ; also at Blue Hill bay in Maine. 

 Bolton, Chesterfield, Chester, Mass., are other localities. A 

 beautiful blue variety is obtained at Dixon's quarry, Wil- 

 mington, Delaware. 



The name apatite, from the Greek apatao, to deceive, was 

 given in allusion to the mistake of early mineralogists re- 

 specting the nature of some of its varieties. 



8. fluor spar — Fluorid of Calcium, Fluate of Lime. 



Monometric. Cleavage octahedral, perfect. Secondary 

 forms, the following : 



Rarely occurs fibrous ; often compact, coarse or fine gran- 

 ular. Colors usually bright ; white, or some shade of light 

 green, purple, or clear yellow are most common ; rarely 

 rose-red and sky-blue ; colors of massive varieties often 



How is apatite distinguished from beryl? how from carbonates? how 

 prom phosphate of lead? What is said of the crystalline form and 

 [cleavage of fluor spar ? What i < said of its colors anu appearance ? 

 I! 



