388 REPORT OF NATIONAL MUSEUM, 1899. 



as in Specimen No. 61135, U. S. N. M. Also common in parallel grouped 

 and rounded forms and globular incrustations. Dana gives the fol- 

 lowing relative to the known localities: 



This mineral was first discovered at Zimapan in Mexico, by Del Rio. Later 

 obtained among some of the old workings at Wanlockhead in Dnmfriesshire, where 

 it occurs in small globular masses, on calamine, and also in small hexagonal crystals; 

 also at Berezov in the Ural, with pyromorphite; and near Kappel in Carinthia, in 

 crystals; at Undenas, Bolet, Sweden; in the Sierra de Cordoba, Argentine Eepul)lic; 

 South Africa. 



In the United States it occurs sparingly with wulfenite and pyromorj^hite as a 

 coating on limestone, near Sing Sing, New York. In Arizona it is found at the 

 Hamburg, Melissa, and other mines in Yuma County, in brilliant deep red crystals; 

 Vulture, Phcenix, and other mines in Maricopa County; at the Black Prince mine; 

 also the Mammoth gold mine, near Oracle, Pinal County, and in brown barrel- 

 shaped crystals in the Humbug district, Yavapai Coimty. In New Mexico it is 

 found at Lake Valley, Sierra County (endlichite); and the Mimbres mines near 

 Georgetown [Specimen No. 67844, U.S.N. M.]. 



The characteristic mode of occurrence at the Mimbres Mine, above 

 noted, is associated with descloizite in the form of small hopper-shaped 

 crj^stals and drusy or botrj^oidal and globular masses coating the 

 siliceous residues of the limestone in the irregular cavities with which 

 the stone abounds. The color of these coatings varies from beautiful 

 ruby red to light ocherous 3^ellow. The mineral is here nearly alwaj^s 

 associated with descloizites as noted below. 



Uses. — See under descloizite. 



4. Descloizite. 



This is a vanadinate of lead and zinc of the formula -1 (PbZn) O. 

 V2O5, H20 = vanadum pentoxide 22.7 per cent; lead protoxide 55.4 

 percent; zinc oxide 19.7 per cent; water 2.2 per cent. The published 

 analyses show also small amounts of arsenic, copper, iron, manganese 

 and phosphorus. Color, red to brown; luster, greasy; no cleavage; 

 fracture small conchoidal to uneven. Occurs in small prismatic or 

 pyramidal crvstals and in librous, mamillated or massive forms. 

 Often associated with and pseudomorphous after vanadinite. 



ZocaUties and mode of occurrence. — Dana gives the following rela- 

 tive to Occurrence: 



Occurs in small crystals, 1 to 2 millimeters thick, clustered on a siliceous and 

 ferruginous gangue from South America, at the Venus Mine and other points in the 

 Sierra de Cordoba, Argentine Republic, associated with acicular green pyromor- 

 phite, vanadinite, etc. At Kappel, in Carinthia, in small clove-brown rhombic 



octahedrons. 



******* 



Sparingly at the Wheatley Mine, Phoenixville, Pennsylvania, as a thin crystalline 

 crust on wulfenite, (piartz, and a ferruginous clay. Abundant at the Sierra Grande 

 Mine, Lake Valley, Sierra County, New Mexico, in red to nearly black crystals, 

 pyramidal and prismatic in habit, associated with vanadinite, iodryite, etc. ; at the 

 Mimbres and other mines, near Georgetown, New Mexico, in stalactitic crystalline 



