58 
MUSEUM BULLETIN NO. 27. 
was sixteen ; these forms are given in the following table, which also shows 
how they were distributed among the differently coloured crystals. 
Crystal Forms of Vestmanite. 
Letter 
Symbol 
Lilac to 
colourless 
Emerald- 
green 
Pale yellow 
Reddish- 
brown 
c 
a 
m 
f 
h 
9 
t 
b 
P 
s 
i 
d 
z 
o 
r 
v 
001 
010 
110 
120 
130 
350 
331 
221 
111 
131 
132 
241 
121 
Oil 
461 
151 
x 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
X 
No new forms were noted, and all those observed are commonly 
occurring and well established forms for vesuvianite, with the possible 
exception of the two last. Of these, v(151) has been observed as a 
rare form, and has also been recently recorded by Schaller 1 on brown- 
green crystals from Alaska. In the present case it was observed as very 
minute facets on the pale yellow crystals from the Montreal chrome pit, 
the mean measured and the calculated angles being as follows : 
Measured Calculated 
v(151) 
J 9 = 11* 
I P = 69 
2V 
44 
11°18' 
69 57 
As has already been noted the same form probably occurs on the 
lilac crystals from this locality, together with y(411) and (272), these 
three all lying in the striated zone (100) : (311). 
The other form, r(461), is marked as doubtful in Goldschmidt’s 
Tabellen. It was here observed on one of the emerald-green crystals, 
and although quite small, the measured angles agree so nearly with the 
calculated values that the form may be considered as well established. 
Measured 
Calculated 
33° 41' 
75 32 
It has not been thought necessary to give the means of the angles, 
as measured, for the other forms, since they agree in every case, within 
a few minutes, with the accepted values, using the co-ordinate p 0 ” q 0 — 
0*5376 or the axial ratio a: c — 1: 0*5376. 
Min. notes, Ser. I, U.S. Geol. Surv., Bull. No. 490. p. 9. 
