f 



Fourth Supplement to Dana's Mineralogy. 117 



bro-wnish black, greenish gray, or n?h-gray color ; and are evitlontly worn cry^;tal9, 

 one of them showing the form of a cube. The mhieral most commonly found among 

 the imported black diamonds or carbonate, are tourmaline, zircon, garnet, broTvn 

 etaurotide, rutile. and a black ore of tantalum. Occasionally grains of gold occur in 

 tlie carbonate^ showing that the age of the material is that of the gold rocks. 

 Observations on the Koh-i-Noor, Amer. J. Sci. [2], xxii, 278, 



Dolomite [p. 441, and I, II]. — Twins in the dolomite crystals of Traversella are 

 figured by Q. Sella in Studii sulla Min, Sarda, Turin, 1856. 



DuKRENiiE [p. 427].— According to Dr. F. A. Genth (Am. J. Sci. [2], xxiii, 42??), 

 dufrenite occurs as a fibrous coating, J th to -J- in. thick, in the greensand forma- 

 tion at Ailentown, I^cw Jersey. Color dark leek-green ; changing to brown as it 

 passes to limonite. Analysis of the green part by 0. A. Kurlbaum, Jr. : 



^ 32-61 3Pe 53-74: te 3"7Y fl 10*49 Si 0*72 =:: 100-95 



Oxygen ratio for R, S, ^, fl, 0*84 : 16-10 : 18*28 : 9*32. Dr. Genth regards the min- 

 eral as containing, through its alteration, some vivianite, and as having the formula 



DcFRENOTSiTE [p. 77 and I, II, III]. — This is the gray prismatic sulpho-arseniuret 

 from the valley of Blnnen. Crystalline form, according to Descloizeaux (Ann. des 

 Mines, viii, 389), trimetric. One fine crystal 33 mm. long, 12 broad, and 7 thick; 

 others smaller. Cleavage brachy diagonal distinct and rather easy ; also basal dis- 

 tinct; also parallel to 21 /: 7=118° V\ 0\ H=149° 1' for other brachydomes, 



O : 4-2 = 175° 8\ 0:^^ = 173° 12', 0:^1 = 171° 31', : ^1 = 168° 45', 

 O : 4i=lG3° 20', : f i = 155° 24', : 2t=-129° 58', : ft=]23° 50' ; 



macrodomes, : -^7 = 153^ 35', 0:^^^7 = 160^28', : ^^^ = 157° 31', 



0:^7=148° 10', 0: 17=128^ 51', :^7r=lll° 50'. Other planes observed, 



*X il. f^ ¥. T%h ih ¥. rh ih \<\^^. ¥^ ¥?■ O : ^=149° 55\ 

 0:^5^=154^4', O:t&^=160°6', 0;|=144°5', 0:^=134° 36', : |= 



126'^ 29', 0:^=116° 15', : ^=103° 51', 0: 4=102° 10'- Descloizeaux 

 also mentions some planes situated obliquely on the angles, uhose exact position 

 has not been ascertained. 



The prismatic crystals are sometimes penetrated by dodecahedrons, which accord- 

 ing to the analyses of M. Uhrlaub pertain to a variety of teunantite, and it is pos- 

 sible that tlie mineral analyzed by Damour has some traces of mixture. 



Descloizeaux objects to substituting the name Bbinite for the prismatic crystals 

 (v- "Waltershausen's scleroclase), and using Dufreiwi^dte for the raonometric sulpho- 

 arseniuret of copper, as suggested by M. Heusser, as it "would only make confusion. 

 He remarks that the name Bbinitc might better be given to the monometric ten- 

 nantite-like mineral, 



"* EiSEXNicKKLEiEs of Schecrer [p. 42]. — Named Nicopyrlte by Shepard in his Min., 



3d edit. 1856, p. 307. 



J 



Enargite [p. 87, 506]. — An ore of an iron-gray color and trimetric in crystaUiza- 

 tion, occurring in small grains or imperfect crystals in a compact quartz rock in 

 Chesterfield District, S. C, at Brewer's Mine, is referred with a query to enargite by 

 Dr. F. A. Genth (this Jour., [2], xxiii, 420). — An imperfect analysis afforded : 



Sulphur 33*78 Arsenic 15-63 Copper 50-59 — 100. 

 ^ The ore was discovered by Oscar M. Licber, Geol Survey of S. Carolina, 



EriDOTE [p. 206 and II, II].— The 2omie of the Saualpe in Carinthia, analyzed by 

 Klaproth has been recently examined by Rammckbcrg (Pugg, c, 133). The angles 

 closely approximate to those of epidote, if the axis supposed by Brooke to be the 

 orthoSiagonal is the clinodiagonal, that is, if tlic prism De turned around 90°, 116° 

 16', given as the prismatic angle of zoisite, being nearly the supplement of 63° 8', 

 the angle 7: / of Epidote, and 1 on the cleavage plane being in the former 121^ 52', 

 in the Tatter 121° 34'. Analyses of Zoisite of different localities by Ramnielsberg ; 



« 



