Whiorephecite: ag3 
Ty. DOMESTIC: 
i. Chlorophete. 
from Professor Edward Hitchcock} 
i feund a mineral several months ago, in the trap Foeks 
about Turner’s Falls, in Gill, Massachusetts, which Professor 
J. W. Webster of Harvard University pronounced to be the 
ehleropheite of Macculloch; and he has announced it as 
such in the Boston Journal of Philosophy and the Arts. The 
following ts a short aceount of the mineral, as it exists at that 
locality. 
It occurs for the most part in radiated masses, from the size 
ef a pea to that of an ounce bullet. Several of these masses 
are frequently united, filling a cavity sometimes two inches in 
diameter. Sometimes the cavity is partly filled with calcare- 
gus spar, and more rarely the ehlorophceite completely in- 
vests the spar. When newly broken in the interior of the 
vock, it is of a yellow green, or dark boitle green, and in some 
instances it 1s semi-transparent in small pieces. But on ex- 
posure to the air it turns darker: the change becomes obvi- 
eus in half an hour, when the mineral is exposed to the 
direct rays of the sun; and ina few hours it is nearly black. 
As this change is going on, the radiated structure becomes 
fess and less distinct, and in some specimens of a jet black 
colour it is scarcely to be discerned. All the nodules that 
appear at the surface of the rock have undergone this change 
ef colour, and become black, dark green, or the dull mee 
green ofsteatite ; andthe specimens are affected in the same man 
ner to the depth of an inch, sometimes more, in the rock ; al- _ 
though the rock is extremely tough and impervious. Some 
specimens, however, both on the surface and within the rock, 
are of a dark cinnamon colour; others, Jong exposed, be- 
come covered with rusty powder. It is so soft as easily to 
be scratched by the finger nail. 
The chloropheite exists abundantly at this locality, which 
iS a projecting bed of greenstone in sandstone, about eighty 
¥ods below the principal cataract of Turner’s Falls, on the 
north shore, twenty or thirty rods above the mouth of Fall ri- 
ver. Indurated clay, however, sgems in this rock to have 
50 
Von. X. No.9. 
