Teates and Ay res — Occurrence of Plattnerite, etc. 407 



Art. L. — Plattnerite, and its Occurrence near Jfullan, 

 Idaho ; by William S. Yeates, with Crystallographic 

 Notes ; by Edward F. Ayres. 



[Read before tbe Chemical section of the American Association for the Advance- 

 ment of Science at the meeting in August, 1891, at Washington,' D. C, and pub- 

 lished by permission of the Assistant Secretary of the Smithsonian Institution.] 



Under the name, Schwerbleierz, in tbe year 1837, lead di- 

 oxide as a mineral species was described by Breithaupt* A 

 quantitative determination of the lead by Plattner was given. 

 As to its occurrence, Breithauptf says, that the only piece of the 

 mineral obtained by him was a large botryoidal mass formed 

 of concentric layers, almost entirely covered by cerussite, 

 pyromorphite and leadhillite. Also, that he did not know 

 the place of its occurrence; but, as the last-named mineral 

 was then known to occur only at Leadhills, Scotland, he 

 concluded, that the " Schwerbleierz " was probably found 

 at that locality. The mineral is described as having a metallic- 

 adamantine luster, becoming dull by tarnish; in color, iron- 

 black, with brown streak ; opaque ; crystallized and massive, 

 the crystals, rhombohedral, in hexagonal prisms with the com- 

 bination, P, ocP, OP ; indistinctly cleavable ; fracture, uneven ; 

 brittle ; specific gravity, 9 - 392 and 9'448, the result of two 

 determinations. Some years after the mineral was described 

 by Breithaupt, Haidinger^: gave it the name of plattnerite, and, 

 a little later, Hausmann§ called it braunbleioxyd. In 1858, 

 Greg and Lettsomf used the name plattnerite, in describing 

 the species in their mineralogy, and added this note : — " The 

 authors can learn nothing more about this species, and con- 

 sider it a doubtful one. The specific gravity seems too high 

 to. be correct, since it is double that of minium, and even 

 more than that of galena. The crystals, described as being 

 hexagonal prisms, may possibly have been pseudomorphous of 

 pyromorphite." In Dana's Mineralogy,^ under plattnerite, 

 the following comment is made : — " A doubtful species. The 

 specific gravity given is as high as that of the protoxyd of lead." 



In a paper read before the Mineralogical Society of London, 

 June 22nd, 1886, Prof. Edward Kinch** described a well authen- 

 ticated specimen of plattnerite from Leadhills, Scotland, giving 



* J. pr. Ch. (1837), x, p. 508. f Loc. cit. 



{Handb. der Best. Minn. (1845), p. 504. 



S Handb. der Min. (1847), p. 202. 



|| Manual of Min. (1858). p. 389. 



^[ A System of Mineralogy, by James D. Dana (1868), p. 167. 



**Min. Mag. London, vol. vii, p. 63 (1886). 



