414 



DESCRIPTIVE MINERALOGY. 



Fig. 494. Fig. 495. with the solid angles replaced by tangent 



planes, as in Figs. 494 and 495. 



At Mineral point on Black lake, the sanae 

 mineral occurs with similar associates as those 

 at Rossie, in the form of the regular octahedron 

 (Fig. 489), and of the octahedron with two or 

 more solid angles replaced by tangent planes. 

 Sullivan County. I have heretofore given 

 a full description of the deposits of galena which occur in the vicinity of Wurtzboro'. The 

 mine which is there described as belonging to the New- York and Shawangunk Mining Com- 

 pany, has passed into the hands of the " Sullivan Company." From information recently 

 received, it appears that the ore, which is very abundant, yields about twenty-two per cent, 

 of metallic lead, and about fifty per cent, of zinc blende. No attempts have yet been made 

 to reduce the zinc ore. 



As this mine is one of the most extensive in the State, and has been very judiciously 

 worked, I was desirous of introducing a section of it into this work. The present proprietors 

 have obligingly furnished me with copies of the drawings made in May, 1840, by Mr. John 

 HiTZ. A large quantity of ore was then obtained, and since that time the works have not 

 been extended. The ore at this locality is almost entirely massive. A few specimens of 

 small octahedral crystals have, however, been found. 



Galena exists in veins at Southampton and Northampton in Massachusetts ; at Middletown, 

 Huntington, Southington and Brookfield in Connecticut ; at Perkiomen in Pennsylvania ; 

 and also in the States of Vermont and Maine. But the most extensive deposits of this ore, 

 found in the world, occur on the Upper Mississipi. 



WHITE LEAD ORE. 



Plomb Carbonate. Hauy. — Carbonate of Lead. Ckavcland, Tlumson and Phillips. — Diprismatic Lead Spar. 

 Jameson. — Diprismatischer Blei-Baryt. Mohs.- — White Lead Ore. Shepard. — Ceruse. Beudant. 



Fig. 496. Description. Colour white, passing into grey and greyish black ; 



also green and blue by admixtures of copper. It occurs regularly 

 crystallized, and also massive and pulverulent. Primary form a right 

 rhombic prism, Fig. 496. M on M' 117°. Cleavage parallel to the 

 planes P, M and M', but not distinctly. Fracture uneven and con- 

 choidal. Lustre adamantine, more or less resinous, and imperfect 

 metallic. Transparent to translucent. Hardness from 3.0 to 3.5. 

 Specific gravity from 6.46 to 6.73. Before the blowpipe, it decrepi- 

 tates, and changes its colour into yellow and red ; upon charcoal, it is 

 easily reduced. When thrown in powder upon ignited charcoal, it yields a phosphorescent 

 light. It is soluble with eflfervescence in nitric acid. When a bar of zinc is introduced into 

 the solution, it is soon covered with blades of metallic lead. 



