452 DESCRIPTIVE MINERALOGY. 



before the blowpipe, but does not give out the odour of arsenic. Composed of iron 97.44, 

 arsenic 1 .56. 



Bedford county, Pennsylvania; Randolph county, Nortii-Carolina (Shcpard). 



MASONITE.* 



Colour brown or blackish ? In tabular crystals, the primary of which seems to be a right 

 rhombic prism. Scratches glass. Specific gravity 3.45. Fusible with difficulty into a dark 

 green enamel. Composed of silica 33.20, alumina 29.00, protoxide of iron 25.93, oxide of 

 manganese 6.00, magnesia 0.24, water 4.00. 



Near Wickford, Rhode-Island, in bowlders ; also in Ward, Worcester county, Mass. 



MICROLITE.t 



Colour straw yellow to reddish brown. Crystallized. Primary a regular octahedron. 

 Lustre resinous. Hardness 5.0 to 5.5. Specific gravity 4.75 to 5.00. Infusible before 

 the blowpipe. 



Chesterfield, Massachusetts, in a vein of albitc, with tourmaline. The crystals are very 

 minute. 



M0NAZITE4 



Colour hyacindi red to reddish brown. Crystallized. Primary an oblique rhombic prism. 

 M on M' 95° 30'. Lustre vitreous to adamantine. Transparent to translucent. Hardness 

 5.0. Sp. gr. 4.99 to 5.08. Infusible before the blowpipe. Composed of peroxide of 

 cerium, thorina, peroxide of tin, phosphoric acid, etc. 



Norwich, Connecticut, with bucholzite. 



NATIVE GOLD. 



Colour bright yellow. Crystallized, capillary, ramified, in grains, and in masses. Soft, 

 flexible and malleable. Lustre metallic. Hardness 2.5 to 3.0. Sp.gr. 17.00 to 19.00. 

 It usually contains small proportions of silver and iron. Melts easily. 



In various parts of the United States, from Canada to Georgia ; seldom, however, in quan- 

 tities large enough for profitable exploration. 



^ C T. Jackson. Geological Sy;rvey of Rhode-IslamJ, ISIO. f Shepaid. American Journal of Science. XXV'II. 3G1, 



t Diina. System of Miner alogy. 



