Mineralogy and Geology. 7 
Com mg dion. nt Si+sAl2 Sif+s cpm 30:58, alumina 50: 99," . 
lime 13: 965 water 4°47. Analyses : 1, J. Lawrence Smith, (Am. J. 
drs hea. a Sei. (21, viii, 379) ; 5, 6, ibid, (private communica wand 3 
7, C. Hartshorne, in Laboratory of J. C. Booth, (private communication 
from Prof. J. C. Booth) ; 8, Silliman, Jr., (private communication) : 
Si 2% Ga Mg Na K — 
i Asin Mise or, 380° 50° 13 Mn, a ple =100,8. 
2. Village Green, 32°31 49°24 10°66 0°30 _ (loss) % pai=i00, Cra 
3. 31:06 51°50 9°24 0-28 100, Garw. 
4, “ 31:26 51°60 10°15 050 et “ read pn Craw. 
5. 30°18 51:40 10°87 0-92 “ 0-54 eel Cou 
6. Unionville at ‘50°57 11°31 0°62 0°85 5°14=100, Cra 3 
‘15 54°28 11°36 vee adetermined oh0 Fe trace, Hartshe orne 
8. North Carolina, na 17 4840 9871 99,HF 2:03=100°80, S. Jr. 
Analyses 6, Tyare of the Corundellite, and 8, of the Clingmanite. 
oa following are the oxygen ratios for the protoxyds, peroxyds, and 
si 
1 420 .<¢>? 24403) 1669 ise 108 626 : 4 
2. 287.3: 38:01: : .16-19. =. 999 648 : 4 
3 3°43 23°93 1@14 -== (85 693 : 4 
4 3°40 24°12 16°24 = 085 594 : 4 
5 4:03 24-02 1666 °“S=" *1US (is) 
6 4°01 23°64 1609: = 1-17 608 : 4 
7 365% 5°37 1658 =, O03 608 : 4 
8 3°99 23°92 ne =... 4°08 604 : 4 
Mean =o 6307 S'S 
@ Supposing the alkalies equivalent to the loss. 
€ mean result is quite closely 1: 6: 4, and the same is afforded 
by several of the particular results. As Dr. Smith found no water, and 
Hartshorne only 0-5 per cent., the species is primarily age - 
cluding the water found by Craw in his meee ye ratio is 1; 6: 
Commonly yields water in a matrass, with s trace of nd 
orine. B.B. exfoliates and emits a bright light aad finally fuses on the 
Asia Minot, and leg at Naxia and Niconia. Also found with corun- 
dum at Corundeli Green, Delaware Co., Pa.; at Unionville, Chester Co., 
ie Silliman, Jr.—Structure as in common mica, but lami- 
nz not as easily separable. Biaxial; angle between the optical axes 
713°, ee Jr. 
H.=3-5—4-5. G.—2-963—3-008. Lustre of cleavage surface bright 
pearly, inclining to adamantine. Color white to colorless ; sides faint 
grayish sea-green or whitish. ee to translucent ; at times 
opaque or nearly so. Laminz rather brittle 
Composition.—Analyses: 1, 2, H. Erni, in the Yale Laboratory, 
‘iv communication) ; 3 3, 4, T. Garrett, in J. C. Booth’s Laboratory, 
n): 
iiladelphia, (private communicatio 
os 
af 
