244 

 LEAD. 



722. MIMETITE. (Arsenate of Lead.) 



a. Crystallized, on psilomelane. 



I. Ditto, containing phosphoric acid (Campylite, Phospho- 



arsenate of Lead). 



Note. Specimen b was probably obtained from Cumberland. See 

 Dana, Mineralogy, p. 537. 



723. CERUSSITE. (White Lead Ore, Carbonate of Lead.) 



a. In slender white prismatic crystals. 



724. CROCOITE. (Chromate of Lead). 



a. Forming a crystalline film on native arsenic. 

 Note. For description and form of crystals, see Dana, Mineralogy, 

 p. 629. >. 



725. PYROMORPHITE. (Phosphate of Lead, Green Lead Ore.) 



a. Crystallized. Two specimens. 



Note. This mineral consists chiefly of phosphate, with some chloride 

 of lead. See Dana, Mineralogy, p. 536. 



726. GALENITE. (Galena, Sulphide of Lead.) 



a. Massive, in cubical pieces. 



&. Massive, surmounted with octahedra. 



c. In cubes, on fluorspar, from Himmelfarth mine, 



Freiberg. 



d. A specimen from Laxey, Isle of Man. 



Note. Specimen e was presented by Mr. E. L. Crow. It contains also 

 copper and blende. 



The following note is appended to the specimen : " This mine (Laxey) 

 yields per month, from a depth of 215 fathoms, 120 tons of lead (each 

 ton containing from fifty to sixty ounces of silver), thirty tons of copper, 

 and from three to four hundred tons of blende." 



For fig. of the crystals of galena, see Dana, Mineralogy, p. 40. 



IRON. 



727. PHARMACOSIDEKITE. (Arsenicated Iron Ore. ) 



a. Crystalline. 



728. SIDERITE. (Carbonate of Iron.) 



a. Crystallized. (Spathose Iron, Brown Spar.) 

 6. Massive, compact. (Clay Iron Stone.) 

 c. Ditto, roasted. 



729. MAGNETITE. (Magnetic Iron Ore, Octahedral Iron Ore.) 



a. Massive. 



I. In distinct octahedra. Eight crystals. 

 Note. See Dana, Mineralogy, p. 149. 



