254 Mineralogical Notices. 
usual ive the areemaier of diorites; attacked by sulphuric acid. 
Composit 
Si fe, Mn Oa Mg Na . K ign 
53:05 2866 090 trae 637 151 412 280 240=9981 
It is a variety of labradorite. Delesse concludes that the radiated 
strueture is found more especially in feldspars containing the 
see proportions of silica 
8. Aphanite of Saint-Bresson (Haute-Saéne. )—The color is 
deep green, verging towards grayish black. It is very tough a and 
compact. It fuses easily in a glass furnace and affords an obsid- 
ian about as hard as that of feldspar. G.=2-968. Composition :— 
Si Ale Mn Oa Mg (diff) Na K ign. 
4683 3033 trace 955 686 357 O87  199=100 
The small proportion of silica is worthy of note. The main in- 
-gredient is a feldspathic paste, which it is difficult to assign to 
gras 
| en papers of the Diorite of Faymont.—Lustre a litle greasy 
' and. wh the other characters of andesite. Composit 
Rr m2 Bo = Ca «= Na, K(diff) ign 
See “5938 9667. trace): 6:50 730 1:25=100 
~~ The crystals are often penetrated or. enclosed by quartz, showing 
_ « » that they were formed amid an excess of silica. 
¢ 10. Hornblende of the Diorite of Faymont.—Occurs in black 
Pat + lustrous laminze and in erystals.. Composition :— 
AE, + Fe i ali ee 
on on 2 ie as 29-29 pd - Mian econ i 
Associated ed with the hornblende, there is sometimes black mica, 
¥ yrites, a Bile magnetic iron, an 
4 ‘ e ghee of the porphyry of  Schirmeck. —This feldspar is 
3 Tis oblong and striated, and pertains to the triclinic system. 
ghtly greenish and a little pearly in lustre. G.=2'686. 
opapesition *— 
Si XI, Be Oa Na, . Mg (diff.) ign. 
of » 65°74 18-49 4ii 100=100 
Hick. one be /Tober Schneider of Halle, o. f. pr. 
Me xlix, 3 22.) 
s a _ pe "60 01 ae som oe 3S Logo =oteit-+atiow. 
| 2/Hartz, Mine Gla ach, 76°04 19°61 498 0:28 race * Eroog2matte W+itnW. 
Ae Fe 721 18 54 5-23 040 0:36 —10074=4 he W +MnW. 
2312027 3:96 0:28 015. pga 
