18 Dr. Genth’s Contributions to Mineralogy. : 
The following are the results : 
I. II. If. FY, Calculated. 
eee ae em aa eee 
From D. Barnhardt’s land. From Pioneer Mills. 
Copper, 47°61 46:69 48:40 4786 4 th Ge = 4814 
Tron, 22°23 22°41 21:08 not det. Fe == 21738 
Sulphur, 29°40 29°76 30°50 not det. r 5, =o SOB8 
Silver, trace 
The composition is expressed by the formula: 2Cu2S+Fe2S;, 
which is between that of yellow copper pyrites=Cu2S+Fe:Ss 
and Erubescite =3Cu2S+Fe:Ss. | 
I have found this mineral associated with other copper ores at 
Dan. Barnhardt’s land (hence its name) and Pioneer Mills, Cabar- 
rus county ; Dr. O. Dieffenbach observed it at the Phcenix and 
Vanderburg Mines of the same county, and I saw it also amongst 
copper ores from the neighborhood of Charlotte, Mecklenburg 
county, N. C. It seems to be abundant in North Carolina, and is 
of course a very valuable copper ore. 
b. I will mention jak another copper ore, which also occurs 
on Dan. Baruhardt’s 
It is massive and caacribies copper pyrites, but is somewhat 
paler. ‘The material for analysis was te aie in appearance and 
seemed not to be a mixture es twos 
Bpee 
The analyses made by Messrs. Wm. J. Payor (1) and Charles } 
Froebel (II), gave the following results 
I. IL. : 
Copper, 40°2 405 5 equiv. Copper brevis 67 
Tron, 284 28-3 4 28:12 
Sulphur, 32:9 311 es Sulphur = 3221 
The composition of this mineral may be expressed by the 
formula: (2Cuz:S+Fe2S3)+(CuS, + 2FeS.) 
Whether further investigations will prove this to be a distinct 
species or not, I am not able to say ; for the present I only wish 
to call the attention of mineralogists to this subject. 
9. Gray Copper, (Fahlerz.) 
In the Am. Journ. of Sc., 2d Ser., vol. xvi, page 83, I have de- 
scribed the first mineral belonging to this group, which has been 
observed in this country. Since then I have found two new 
localities, where minerals occur belonging to this group, and a 
third one (Duchess county, N. Y.) was mentioned to me by Dr. 
From is Bidees Gold Mine, Buckingham county, Va.— 
ranular masses ; lustre metallic; color between iron-black 
; streak iron-black ; opaque; =4. oe brittle ; ; 
—subconchoidal. 
face aneven= 
