Geology and Mineralogy of a part of Massachusetts, $c. 49 
25. AMIANTHOIDE ? 
Very minute fibres, associated with actynolile, idocrase, 
and hornblende——fusible into a dark dull enamel. Emmons. 
1 mention this mineral to excite attention to it. It may be 
fibrous actynolite, and it may be amianthoide. The two 
seem to be closely related, and do not differ very greatly 
in their composition. 
26.. DIALLAGE? 
In Diallage rock? Chester. It resembles metalloidal 
diallage. It differs so much from hornblende in its gene- 
ral appearance, that I suspect it to be diallage. In the 
serpentine of Middlefield is a foliated mineral in small 
quantity, which seems to be metalloidal diallage, though it 
is rather finer grained than the European which I have 
seen. 
27. SERPENTINE. 
In immense quantities in a bed two miles long in Mid- 
dlefield, two miles south of the meeting-house. It often 
forms ledges from 50 or 80 feet in height, and is of various 
colors, light and dark green, and dark reddish brown like 
specimens from England. In a neighboring brook, it is 
white and cream colored, sometimes spotted, translucent, 
and beautiful. Both precious and common serpentine are 
found here. The green and brown are acted upon by the 
weather, and the surface becomes of a reddish yellow 
color, and they sometimes disintegrate into a reddish earth. 
The rocks break into angular fragments, with an obvious 
tendency in many cases to prismatic forms. In Russell, a 
little east of south from this place, it occurs in large beds, 
of avery dark green, nearly black, and has been polished 
for marble. (See Am. Journ. Vol. III. page 238, for a 
particular account of the serpentine in Russell.) In- 
deed the serpentine in the whole range will take 
a fine polish. Another bed is east of the meeting- 
house in Middlefield, connected with the great bed of 
steatite. Serpentine is found also in the N. W. part of 
Vou. VIIT.—No. 1. a 
