118 NEW YORK STATE MUSEUM 



masses or nodules not unlike common limestone. The luster is 

 vitreous to resinous and the color varies widely from sea-green, 

 bluish green, brown or flesh-red, in the commoner occurrences, to 

 transparent violet, yellow or colorless and opaque white or gray 

 in the less common forms. 



VARIETIES 



Ordinary. Crystallized or granular massive material as de- 

 scribed above. 



Phosphorite. Fibrous concretionary and partly scaly masses. 



Osteolite. Mostly altered and impure apatite of a compact 

 earthly nature and white or gray in color. ^ 



RELATED 



Phosphate rock. A massive impure phosphatic material chiefly 

 of organic origin, and granular, spongelike or nodular in struc- 

 ture. Here are included the phosphatic limestones, guano 

 deposits and bone beds from which is extracted material of con- 

 siderable importance in the manufacture of fertilizers. 



Apatite occurs in a great variety of formations but is most 

 common in metamorphic crystalline rocks particularly in granu- 

 lar limestone, in gneiss, syenite, mica schist and in beds of 

 iron ore. As an accessory rock mineral it has a wide distribu- 

 tion. It is found in many igneous rocks, the larger crystals 

 being characteristic of granite and pegmatite, where it is asso- 

 ciated with quartz, feldspar, tourmalin, muscovite, beryl, etc. 



Besides many foreign localities apatite occurs in extensive 

 deposits in the Laurentian gneiss of Canada associated with 

 calcite, pyroxene, amphibole, titanite, etc. It is found in Maine, 

 New Hampshire, Massachusetts, Connecticut, and in New York, 

 in St Lawrence, Jefferson, Essex and Orange counties; also in 

 Pennsylvania and North Carolina. Extensive deposits of phos- 

 phate rock occur in eastern South Carolina and Florida. 



Apatite in the form of phosphate rock is largely used for 

 fertilizers. The purer material is employed in the manufacture 

 of phosphorus. 



Pyromorphite (green lead ore) (PbCl)Pb 4 (P0 4 ) :! 

 Pyromorphite is a phosphate of lead with lead chlorid, often 

 with some arsenic, iron or calcium. With a larger proportion 

 of arsenic it passes into mimetite. 



