© <j me "Tgp 
3 Te 
i 
400 Fifth Supplement to Dana's Mineralogy. 
Gypsum.—TI: I=111° 22’: plane of axes i+ at any pigete rt at 9°4 C., 
the — — 37° 28' to normal to -2; at 9° C., ’; at 80° C. 
the nite and are contiised with thei bis miittns ‘xioedl 0°, they 
‘ nant bs bat in a plane normal to 7-2. a=1'52975, B= 152267, y= = rien, ; 
for the yellow rays Gaduhad oe an alcohol vd prthte ig salt, at the tem- 
perature of 19° C,, according to Angstrém; whenee 2V=57° 
C. Crystallization Triclinie. 
me Sami rd = apparently normal * the edge 7: J’, and tilled shee 18s 
; bisectrix inclined 109-12 to a normal to ai, and 8 
0812 39) i a ohana to 0. Angle hivies the axes as great as in ri 
it not 
Eabradoriie pee a as in Albite. Mean index 1:80, Heuss 
Apothte Soamy as in Albite; but plane of the axes “ry quite normal to 
d 
eee 
g 
Ofigotane-—Nearhy as in Albite ; plane of the axes ping normal to 2-% and to the 
edge I: J’. The rings seen thro ough the cleavage face ery fine. 
Cryolite-—Probably ‘tglelinic Plane of the axes and bseti making an angle o 
about 35° with a normal to one of the cleavage fac 
2. Negative. 
A. Crystallization Trimetriec. 
— Bisectrix. 2V. 2E. 
Tolite, Ceylon, - {119°10/| «2% | norm.O | -°69° 3’ “ 121° 46’ 
enmais, ib. ib. 70° 4/ 124° 24 
« — Orrijarfvi, - ib. ib. 69°57’ 123° 38 
? - ddam, - ib. ib. 37° 48/ 60° 46"! 
Stilbite, - - | 94°16'| ét ib. 61°, Dz. . 
Min, ee 2 Oe norm ib. 
i - = (190° [i¥ diz) — ib. eon bw 
- |120°+ | it ib. 7° 24/, Br. . 
Py sip - norm.O oan 110°+, Dz. | 3 
Py ° f nor ib. “1 
Aragonit 116° 10 2-70 1 toe 18° 197 he: 30° 50’, Dz. 
Witherite, - - |118°30°]  é- ib. 
Alstonite, - |118°51"| 6% ib. 
Strontanite s |1T7°19"| # ib. 6° 56’ 
Cerus - |116°10'| ¢-% ib. 28° 8/ 
. lobs. 8° 16’, Af. 
hillite, - |120°20°| #¥ ib. 10° 35’, Br. 
' omite, - - | 90°34} O | par.mac.} 50° 62! 
Zine Vitriol, - | 91° 7'| 0 ib. 44° 9!, Sen. 
Hopeite, - - | 120° 26’ norm. é-1. 
. Brookite, - - | 99°50’! © ‘par. brach. 
Ixvex or Rerraction.—Iolite, Ceylon, a 15433, 6 15413, 71 5371}. 
a 1544, eh 41535; Orrijarfvi, a 15396, 815377, 7 15345; Haddam, 
815616, 1'5523.—Aragonite, a1 a A; 163157, 7153013 (ray D, at dt 
ne 11740, Br.~-Strontianite, « 1°700, 7 1-543, Br—Cerusite, « 20745, B2 
Dx.; 82067, M.—Leadhillite, 8+: 1- ath. Epona @ 1-4817.——Zi ine Vitra es 
B. Crystallization Monoclinic. 
Orthoclase—I: J=118° 48’; plane of the aay ioe perpendicular | 
clined 21° 7’ toa ‘rpen ‘oe ii ii and 95° to a normal to O: ee * 
becomes e ase on parallel ra ii Biseetrix making 
ng of about 5° Wtiihe 6 n adu 19126". i 
260, 8==1'5237, y=1 ‘5190; whitnca. aves69° 43" = 2E=1 
