1835.] Mineralogy and Petrography. 709 
Belgrade. An analysis of the purest specimen, which was, how- 
80, OBE A O Fao; Me Grote BL as 
56.13 14.59 14.37 3.54 1.10 0.43 1.68 2.39 5.38 
6th. Zunyite—Mr. Hillebrand? of the U. S. Geol. Survey, now 
stationed at Denver, Col., describes remarkable tetrahedral crys- 
tals of a new mineral which he found imbedded in an uncrystal- 
lized sulphide of lead and arsenic, occurring at the Zuñi mine on 
nvil mountain, near Silverton, San Juan county, Col. These 
crystals are mostly very minute, rarely 5™" in diameter. 
They show the forms 2 — =f eretdsOe— 
, and are quite 
isotropic. The smallest are clear and transparent; the larger 
ones dark on account of black inclusions. Sp. gr. 2.875 at 15°C. 
Luster glossy, cleavage octahedral, hardness 7. The mean of 
several analyses gave : 
BOLO PAO TANO EO N0 ORO: Fo, F A 
24.33 0.20 57.88 0.10 0.24 10.89 0.60 5.61 2.91 
sum 102.76 — O for Cl and F (3.02) = 99.74. 
Formula, 9R,O, 8A1,0;, 6SiO., with part of the O replaced by 
Cl and F. The black inclusions were shown to be titanic oxide. 
7th. Guitermanite—The metallic sulphide in which the above 
described crystals of zunyite were imbedded, was found to have 
_ the composition 1oPbS, 3As.S,, being likewise a new mineral to 
which the same author applies the name Guitermanite. 
8th. Koninckite—M. Cesàro? has recently described a new hy- 
drous phosphate of iron from Visé in Belgium. It occurs in 
spherical groups of radiating, nearly colorless monoclinic needles 
associated with richellite, another new mineral lately described by 
the same author (vid. NaTuratist, Jan., 1884, p. 65.) Koninckite 
has one perfect cleavage, H = 3.5; G= 2.3. Its composition is: 
P,O, Fe,O, H,O Al,O, (difference) total 
38.4 33-9 26.8 4.5 100 
It is named after Professor De Koninck of Liége. 
oth. Endlichite or vanadium mimetite—Professor Gentht has 
found that certain straw-yellow crystals occurring at the sil- 
ver mines of Southern New Mexico have the composition 
l Berichte der deutschen chemischen Gesell., xvir, No. 13, p. 1774, Aug., 1884. 
? Proceedings of the Colorado Scientific Society, Vol. 1, 1883-84, p-124. i 
3 Mem. Soc. Geol. Belgique, XI, p. 247. : 
‘Contributions from the Laboratory of the University of Pennsylvania, No, XXIL 
Read before the American Philosophical Society, April 17, 1885. 
