






214 IDA A. BROWN. 
I. II. IIT. LV. |= ivR 
Spec. Gravity) 3°286* 3°218 | 3:283 3°226 
| Si0, 44°97 738 45-00 41-67 39°95 
| Al,O, 9°56 93 9°41 11°38 17°58 
| Fe,0O, O-1ll l 1:55 183 25 
| FeO Wad 242 16°76 16°28 2°18 
l= Ca® 11°30 202 11°24 11°35 11°96 
MgO 10°83 271 IES IL) 10:29 14°15 
Na,O 1°19 19 1°66 By r(0) 3°16 
| K,O+ 0:75 8 1°36 0:96 1:98 
| H,O- 2219 12 Negy5) 2°18 0-41 
iO 0:04 ae se “eal 
We Li@s 2°36 28 ee 0°85 1°68 
| MnO n. d. 0°33 tr. 
eB "03 
| 
| 100:01 99°85 |100°55 |100°46 
| O=F, be oe ae a ‘Ol 
| 100:45 


* Pi 
I. Hornblende from hypersthene gabbro, Broken Hill, N.S.W-. 
If. Molecular numbers for column |. 
III. Black hornblende occurring with labradorite, Glen Bucket. 
Hintze, Handbuch der Mineralogie, IT,, (p) cxx, p. 1237. 
TV. Black hornblende, Edenville, N.Y. Hintze, Handbuch der 
Mineralogie, II,, (u) coxxu, p. 1241. 
V. Basaltic hornblende from Bilin, Bohemia. 8S. L. Penfield and 
F.C. Stanley, Amer. Jour. Sci., xx111, 1907, p. 47. 
From the analysis it may be seen that the mineral is a 
relatively rare type, the analyses given in columns (III) 
and (IV) being the only ones, out of several hundreds 
examined, which could be compared with it. For com- 
parison, the analysis of typical basaltic hornblende is given | 
in column V. The chief difference lies in the high percentage 
of ferrous oxide, with low ferric oxide and relatively low 
alumina, in the hornblende under consideration as compared 
with basaltic hornblende. The specific gravity of this 
hornblende like that from Edenville, is above the average, 
and the titania percentage is also high. 
7 
q 
7 
. 
| 

