IRON. 185 



crystals have been found at Imlaystown, N. J. At Allentown, 

 Monmouth County, and Mullica Hill, Gloucester County, N". 

 J., are other localities. It often fills the interior of certain 

 fossils. Occurs also at Harlem, N. Y., in Somerset and 

 "Worcester counties, Md., and with bog ore in Stafford 

 County, Va. Abundant at Vandreuil in Canada, where it 

 is associated with limonite. 



The blue iron earth is an earthy variety, containing about 30 per 

 cent, of phosphoric acid. 



Ludlamite. A clear green hydrous phosphate of iron in monoclinic 

 crystals ; from Cornwall. 



Dufrenite. A hydrous phosphate of iron sesquioxide. It has a dull 

 green color, and is often found in radiated forms. 



Cacoxenite. Occurs in radiated silky tufts of a yellow or yellow- 

 ish-brown color. H.=3-4. G. =3*38. It is a phosphate of iron 

 sesquioxide, and often contains alumina. It differs from wavellite, 

 which it resembles, in its more yellow color and iron reactions. It 

 also resembles carpholite, but has a deeper color, and does not give 

 the manganese reactions. It occurs on brown iron ore in Bohemia. 



ClialcosideHte and Andrewsite are other iron phosphates. 



Strengite. A hydrous iron phosphate related in formula to scoro- 

 dite. From near Giessen. 



Arsenates of Iron. 



Pluirmacosiderite , or Cube ore. Occurs in cubes of dark green to 

 brown and red colors. Lustre adamantine, not very distinct. Streak 

 greenish or brownish. H.=2%5. G. =3. It is a hydrous arsenate of 

 iron sesquioxide, containing 43 per cent, of arsenic pentoxide. From 

 the Cornwall mines ; also from France and Saxony. 



Scorodite. Crystallizes in rhombic prisms, with an angle of 120° 10' 

 between its secondary prismatic planes. Color pale leek-green or liver 

 brown. Streak uncolored. Lustre vitreous to subadamantine. Sub- 

 transparent to nearly opaque. H.=3'5-4. G. =3*l-33. A hydrous 

 arsenate of iron sesquioxide, containing 50 per cent, of arsenic pen- 

 toxide. From Saxony, Carinthia, Cornwall, and Brazil ; and minute 

 crystals near Edenville, N. Y., with arsenical pyrites. The name of 

 this species is from the Greek skorodon, garlic, alluding to the odor 

 before the blowpipe. Iron sinter is an amorphous form of the same 

 mineral. 



Arseniosiderite is another iron arsenate. 



Siderite.— Spathic Iron. Iron Carbonate. 



Ehombohedral. In rhombohedrons with easy cleavage 

 parallel to a rhombohedron of 107°. Faces often 

 curved. Usually massive, with a foliated struc- 

 ture, somewhat curving. Sometimes in globular 

 concretions or implanted globules. 



Color light grayish to brown; often dark 

 brownish-red. It becomes nearly black on ex- 



