EXTRA-LIMITAL SPKCIES. 455 



pipe, with the evolution of arsenical vapours. Composed of arsenic 68 , 50, cobalt 9 . 60, iron 

 9.70, copper 1.00, sulphur 7.00. 



Chatham, Connecticut, associated with arsenical iron pyrites and copper nickel. 



TEPHROITE. 



Tephroitc. Lconkard. 



Colour ash-grey, liver-brown to black. Massive and compact. Lustre adamantine. Hard- 

 ness 5.0 to 6.0. Sp. gr. 4.10 to 4.12. Before the blowpipe, fuses into a black slag. 



Sparta, New-Jersey, with franklinite. It is supposed by Shepard to be a variety of 

 troostite. 



TIN ORE. 

 Oxide of Tin. Ckaveland. 



Colour white, grey, yellow, red, brown and black. Streak grey or brown. Crystallized 

 and massive. Primary an octahedron with a square base. Lustre adamantine. Semi-trans- 

 parent to transparent. Hardness 6.0 to 7.0. Sp. gr. 6.51 to 7.10. On charcoal, before the 

 blowpipe, it is reduced to the metallic state. Composed of oxide of tin 95.00, oxide of iron 

 5.00. 



Goshen, Massachusetts ; and in considerable quantity in Jackson, New-Hampshire. 



TOPAZ. 



Colour various shades of yellow, green, blue or red. Streak white. Crystallized and 

 massive. Primary a right rhombic prism. M on M' 124° 22'. Lustre vitreous. Translu- 

 cent to transparent. Hardness 8.0. Sp. gr. 3.49 to 3.56. Scarcely fusible before the 

 blowpipe. Composed of alumina 57.45, silica 34.24, fluoric acid 7.75. 



Middletown and Trumbull, Connecticut. A specimen from the vicinity of Carmel in Put- 

 nam county, N. Y., closely resembles topaz ; but the crystals are too small and imperfect to 

 determine positively. 



TRIPLITE. 



Phosphate of Manganese. Ckaveland.. 



Colour blackish brown. Massive. Lustre resinous, inclining to adamantine. Translucent 

 on the edges to opaque. Brittle. Hardness 5.0 to 5.5. Sp. gr. 3.43 to 3.78. Melts be- 

 fore the blowpipe into a black scoria. Composed of oxide of iron 31 .00, oxide of manganese 

 42.00, phosphoric acid 27.00. 



Washington, Connecticut; Sterling, Massachusetts. 



