SILICA. 
275 
cut and turned on a lathe. It is of various colours, from a very light green to nearly black, 
and is susceptible of a line polish. Large blocks have been quarried at this locality, entirely 
free from checks and flaws which so often render this material valueless. 
New-York County. On the Hudson river, near the city, there is a large bed of serpentine, 
with veins of amianthus ;* while the same mineral, entirely resembling that at Hoboken, is 
frequently found in bowlders in the southern part of the island. Dr. Gale states that these 
bowlders are rare in the northern part of the island. 
Onondaga CouNTy. On the hill a short distance east of the mansion of Major Burnet at 
Syracuse, there is a dyke or bed of serpentine, more or less mixed with limestone, and having 
various shades of colour, as bottle green, greyish green, and nearly black. 
These serpentines were first noticed by Mr. Vanuxem, and described by him in his report 
of 1839, and he considers them new varieties for our country. “ Some have a peculiar 
appearance, like bronze, owing to small gold-like particles with a lamellar structure, resem¬ 
bling bronzite or metalloidal diallage. There are also other particles highly translucent, like 
precious serpentine, with frequently small nuclei resembling devitrifications or porcellanites, 
coloured white, yellow, blood-red, variegated, etc. The grain of this kind is like common 
serpentine. In other kinds, the mass seems to be made up of small globuliform concretions, 
varying in size, being centres of aggregation. Some are of dark vitreous serpentine, others 
are of the compact kind, the enveloping part being of a lighter colour.”! 
These principal varieties produce endless mixtures upon the small scale, and numerous 
differences in the shades of colour. 
According to Mr. Vanuxem, these serpentines seem to resemble the ophiolites of Tuscany; 
and should the views of Brocchi be correct, they may not only be similar in origin, but in age. 
In regard to the chemical nature of these minerals, I have observed that all the specimens 
contain a large admixture of carbonate of lime. They almost all effervesce freely in acids ; 
but there is always a nucleus of serpentine. The specimens are susceptible of a polish, and 
when sufficiently compact, and free from seams, exhibit in a striking nnanner the great variety 
of colours which the mineral possesses. 
Orange County. There are several localities of serpentine in the towns of Conrwall, 
Monroe and Warwick. In the Forest of Dean in Cornwall, it is yellow and dark yellowish 
green, in imperfect crystals and grains, in white limestone. 
The common variety of a dark colour is found associated with magnetic iron ore, at the 
O’Neil and Forshee mines in the town of Monroe. The quantity, however, is small. 
There are several localities of the crystallized, massive and disseminated varieties in the 
town of Warwick. One of the most interesting of these is about two miles south of the 
village of Amity. It is found here in imperfect crystals, which are grass-green, yellowish 
green, and nearly black. The crystals are sometimes two and a half inches long and one 
and a half broad; and Dr. Fowler has noticed some, probably from the same locality, which 
J. Van Rensselaer. American Journal of Science. XIV. 192. 
t Vanuxem. New-York Geological Reports, 1839. 
