196 FA. Genth’s Contributions to Mineralogy. 
small for any further examination, I considered this-oceurrence a 
interesting enough to have it recorded. Associated species are, — 
besides those already mentioned, galena, blende, pyrites, tale, 
quartz, diallogite, calcite, barytes, etc. fm 
7, Automolite. it 
The beautiful automolite from the Canton Mine was firstno — 
ticed by Prof. C. U. Shepard (Report on the Canton Mine, Savan- 
nah, 1856, and 2d edit., New Haven, 1856.) The crystals are 
of a very deep leek-green color and vitreous lustre, and presenh 
the octahedral and dodecahedral planes, the latter very deeply 
striated, parallel with the macrodiagonal. An examination 
made in my laboratory gave: 
= — ae 
~ 
is = mn 
= 
Sah 2 Oxygen. 
: ilicie acid, (quartz) 2°37 p.c. 
upric oxy + : 
Alumina, ~ : 53°37 “ contains 2495) 4.95 = 3 
Ferric oxyd, 668 « “ 2°00 
Ferrous oxyd, 301 “ « 0°67 
Ee ee eee 
Magnesia, Bag sd 1:29 
100°35 
The small percentage of silicic acid in the above analysis 1 
sults from a mechanical admixture of quartz; the cupric oxyd 
prey does not belong to the mineral and therefore has nd 
een considered so; taking the iron as magnetic oxyd, whica 8 
most rational on account of the deep leek-green color, we get 
exactly the spinel formula RO: R,O, =1:3. 
8. Pyrope. ia 
A deep blood-red, and sometimes brownish-red variety f | 
ass was several years ago brought from near Santa Fé, New” 
exico. It forms small, somewhat angular grains, of from Nad 
+ of an inch in size, the edges rounded. as if worn off. Sp- 8 
° C. =3°738. An a 
at 12° ©. ysis made in my laboratory gave> 
ae Oxygen. A 
Iguition, = - = = os 
Silicic acid, one 42°11 contains 20°86 
Alumina, - ~~ - 19°35 . 9-04 t 9°85 
ied we 262 # « 081 
Ferrous oxyd, oe 14°87 * 2°30 
‘Manganous oxyd, - - 036 “ 0-08 9-4 
lime, - - eth (oo as ce 149 : 
Magnesia, - - - - MW0l * 5:60 4 
— 99°00 a 
jy Considering anf 
