Sulpharsenites of Lead from the Binnenthal. Part III.—Baumhauerite, a new mineral; and Dufrenoysite

Abstract

For this new mineral I propose the name baumhauerite in honour of Dr. H. Baumhauer, Professor of Mineralogy in the University of Freiburg, Switzerland, who has done so much to elucidate this complicated group of sulpharsenites of lead.System: Oblique. a : b : c = 1.136817 : 1 : 0.947168; β = 82° 423/4.These elements are calculated from the angles 100 : 101=50° 27′ 101:001 = 32° 153/4′ and 010 : 111̄ = 50° 33′ measured on crystal No. I.The crystals closely resemble dufrenoysite and jordanite in appearance. They may be distinguished from dufrenoysite by the marked oblique development of the zone [100,001], and from jordanite by the absence of twin striations and by the colour of the streak. The edges in the pyramid zone and between planes in the zone [100,010] are more or less rounded.