Localities of Minerals. 237 
Hexagonal crystals of mica.—They are in granite. As I 
did not notice them at first, I cannot tell where the granite 
was obtained, but believe it was from Chester or Westfield, 
on the granite ridge. Some of the crystals are small, not 
more than one tenth of an inch on a side and almost regular 
hexagons. Others are larger, and have unequal sides.— 
The real size of them is here given. 
NO GING. 22 Ay 
Thesidesare ¢o—& ee : 
generally very © é oO O Enlarge. 
nn 
perfect, and @ 
some of the crystals much -skeabie those 
you mentioned in the Journal from Perto 
Rico. It is probabie that other specimens of hexagonal 
crystals may be obtained on the granitic ridge in this State. 
An attempt to measure the angles of No. 1, gave angle 
== 1229, O=1269, c==1120, d==121°;  e=108°, . and 
“nN==1320. The sum is 721°, and should be but 720°. 
The above angles may therefore be taken as very near the 
truth, 
In No. 3, the angles were as follows, a=116°, 6=124°, 
c==129°9, d=112°, e=1222°, and n—=117°; being only 
7205°, and approximating nearly to the truth. I do not 
suppose the angles are very accurate, for f had no good 
means of measuring them. In some of the crystals, the 
sides are more unequal than in No. 3. 
In some rhombic spar, containing the new mineral, Bru- 
cite, from Sparta, N. J. I found several hexagonal crystals 
of mica. 
Crystals of Tremolite, in dolomite, from Great Barring- 
ton. ‘These crystals are much compressed, and the diedral 
summits rather rounded, so that they become bladed erys- 
tals. They are from one half inch to two inches, or more, in 
length, and some of them three fourths of an inch in breadth. 
They are found in hard rocks cf dolomite, above ground, 
and very abundantly, in the very friable dolomite, under the 
surface of the earth. The fibrous and acicular varieties of 
tremolite are abundant in the South part of this county. 
Brown Spar from Leicester, N. Y. on Genesee river.—— 
The crystals are rounded, or lenticular, and often so group- 
ed, as to have a scaly appearance—colour, dark brown. 
Mon 2. No: 2° 3] 
