40 
MUSEUM BULLETIN NO. 27. 
The remaining new forms (xi 5i Ni Oi) were observed on one crystal 
only in each case; all were very narrow line faces, which did not yield 
very bright signals. 
Rare Forms. Although about one hundred forms have been recorded 
for diopside, the crystals of this mineral are usually of fairly simple habit. 
A large majority of the recorded forms are rare and have been observed 
only on one or two occasions, or, in the case of many of them, only on 
crystals from one locality. Several such rare forms have been noted 
on the crystals from the Montreal chrome pit, and the history of these 
is given below; these particulars are abstracted from Zambonini’s exhaus- 
tive monograph on diopside 1 and only those are here included which at 
that time (1909) had not been recorded from more than two or three 
localities. 
g. .......... . (210) First observed by Michel-Levy ; recorded by Lewis on crystals 
from Thieralpeli a Tschevwandune, and by Zambonini and 
Sjogren on crystals from Kafveltorp; is present also on crystals 
from Testa Ciarva, Alatale. 
Montreal chrome pit: As a line face on two crystals, one of them 
the twin shown in Figure 13. 
St (140) Observed first by Schmidt, from Schwarzenstein-Alp (Zillertale) . 
Montreal chrome pit : Noted on one crystal of tabular habit as a 
perfectly definite form of fair dimensions. 
F (301) (S of Zambonini). First observed by vom Rath, and later by 
Zambonini on crystals from Testa Ciarva. 
Montreal chrome pit : Observed once on a twin crystal as a face 
of fair size. 
I (702) (J of Zambonini). Noted by La Valle; locality, Testa Ciarva. 
Montreal chrome^ pit : Occurs as a face of fair dimensions on the 
same crystal which bears the face F(3G1). 
M (401) Observed by G5tz, and later by Zambonini; both Testa Ciarva. 
Montreal chrome pit: On one crystal as a face of fair size and 
shown in Figure 7. 
* (501) 
n (102) 
P ....(332) 
First by vom Rath, later by Zambonini; both on crystals from 
Testa Ciarva. Also by La valle on crystals from Borne de 
Brous which is opposite Testa Ciarva, on the other side of Alatale. 
Montreal chrome pit: On several crystals, some of which are 
shown in Figures 7, 10, 13. 
By several observers, on crystals from Testa Ciarva. 
Montreal chrome pit: Present on the twin crystal shown in Figure 
13; also observed on one other crystal, Figure 9. 
On Testa Ciarva crystals. 
Montreal chrome pit: Observed on several crystals. 
W (441) First observed by Cathrein on crystal from Pinzgau, Austria.* 
Montreal chrome pit: Two faces of this very acute hemi-pyramid 
occur on the same crystal, which presents the new orthodome Ji 
(902); they are perfect faces and as will be seen from Figures 7 
and 8 they are very prominently developed. The angles were: 
Measured Calculated 
<p = - 40® 0Q' -39° 42' 
P = 71 56 72 01 
1 Op. dt. 
1 Neue Kryetallformen an Pinzgauer Pyroxen, Von A. Cathrein, Annalen Der K. K. Natmrhist., Hof- 
museums, Vienna, 1889, p. 181. 
