236 Localities of Minerals. 
we 
Art. 1V.—Locauities or MINERALS. 
Localities—communicated by Professor Dewey of Will- 
iams* College. 
curs, 
ish-white, and cream-coloured, with spots of a smoky hue, 
like smoky quartz in this respect, but certainly serpentine. 
It is sometimes associated with quartz, filling the cavities of 
strata of quartz, covered with minute crystals. Its hard- 
ness is very variable—some of it is disintegrating, some Is 
fibrous, and seems to be passing into asbestus. Much of 
this serpentine, especially the lighter coloured, is remarka- 
bly fine. The whitish decrepitates much, when high tem- 
perature is suddenly thrown uponit. Odour is strongly mag- 
nesian, when the mineral is breathed on. In some speci- 
mens are yellowish and reddish brown portions of a crystaline 
structure, and in some, cavities are filled with these impet- 
fect crystals. They break into a rhomboidal form, and are 
sometimes very regular rhomboids. Some of them, are so 
closely serpentine, that they may be all the same mineral. 
They contain, like the rest of the serpentine, magnesia, 0X- 
yd of iron, often so minute, that they are discoverable only 
under a magnifier, or by the magnet. : 
Ir. Emmons has also found, beautiful masses of actyno- 
lite, often containing small tufts of the fibrous variety. White 
talc is often mixed with the actynolite. 
Bitter Spar, is found there also, in the soapstone, 28sec 
ated with beautiful green tale. The spar is laminated, white, 
and yellowish—but some specimens, when fractured, Pte 
sented numerous small rhombs. i 
| have found in Sheffield, (Mass.) masses of Tremolite, 
with fibres two feet long. I never heard of such tremolite. 
* In Prof. Dewey’s piece, (Vol. I. pa. 337,) Williams College is errooe: 
ously printed Willian.’ College. re * 3 
