tthierophetite: ag 
I, DOMESTIC: 
i. Chlorophaiit. 
[From Professor Edward Hitcheock.} 
Y feund a mineral several months ago, in the trap reeks 
about Turner’s Falls, in Gill, Massachusetts, which Professor 
W. Webster of Harvard University pronounced to be the 
thloropheite of Macculloch; and he has announced it as 
such in the Boston Journal of Philosophy and the Arts. The 
pcame is a short aceount of the mineral, as it exists at that 
Ocality. ¥ ae ated 
It ais for the most part in radiated masses, from the size 
of'a pea to that of an ounce bullet. Several of these masses 
are Al = gh Pate filling a cavity sometimes two inches in 
diameter. Sometimes the cavity is partly filled with calcare- 
ous spar, and more rarely the ehlorophaite completely in- 
vests the spar. When newly broken in the interior of the 
rock, it is of a yellow green, or dark bottle green, and in some 
instances it is semi-transparent in small pieces. But on ex- 
posure to the air it turns darker: the change becomes obvi- 
ous 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 
less and less distinct, and in some specimens of a jet black 
colour it is scarcely to be discerned. All the nodules that 
ss 
= 
appear at the surface of the rock have undergone this change 
ef colour, and become black, dark green, or the dull mudd 
ri Peat Pee? : flectedinthesame nan- 
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, long exposed, be- 
tome covered with rusty powder. It is so soft as easily to 
be scratched by the finger nail. a 
The chloropheite exists abundantly at this locality, which 
18 a projecting bed of greenstone in sandstone, about eighty 
rods 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, s¢egms in this rock to have 
Vou. X. No. 2. 99 
