58 
ECONOMICAL MINERALOGY. 
nesia, which, as well as the sulphate, is used for medicinal purposes.* By this operation, 
when serpentine is employed, a large quantity of Venetian red is also procured, as that mineral 
contains a considerable proportion of oxide of iron. This manufacture is now carried on near 
Baltimore in Maryland, and there seems to be no reason why it may not be profitably pursued 
in the vicinity of New-York. 
Serpentine, similar in every respect to that found on Staten Island and at Hoboken in New- 
Jersey, occurs in considerable abundance in the counties of New-York, Westchester, Putnam, 
Rockland and Orange ; and extensive deposits of the same mineral are also found in the county 
of St. Lawrence. 
The beautiful green colour of serpentine, and the fine polish which it takes when pure, give 
it great value as an ornamental' marble. When mixed with granular limestone, it forms the 
celebrated verd antique. Unfortunately in almost all the localities in the southern part of the 
State, at least so far as they have been explored, the serpentine, although in great abundance, 
is so mixed with carbonate of magnesia, asbestus and other magnesian minerals, as to render 
it unfit to be worked as a marble. Thus a block obtained from a quarry in the county of 
Westchester, concerning which high expectations had been raised, was found to have an un¬ 
equal degree of hardness in its different parts, and to be filled with seams and nodules of other 
magnesian minerals which could not be polished, or were too friable to sustain the rough usage 
which is required for the dressing of marble. 
Dr. Emmons informs us that there are several localities in St. Lawrence county, in which 
the soundness of the serpentine rock is remarkable ; and the only impediment to the introduc¬ 
tion of this article for ornamental and useful purposes, he thinks, is the expense of transporta¬ 
tion. At Pitcairn, is a fine locality of verd antique. The colours are green and white, ar¬ 
ranged in the usual forms of clouded marble. The serpentine has a bright green colour, and 
belongs to the Variety usually called precious. The carbonate of lime is white, and forms a 
handsome ground for the translucent serpentined 
Usually associated with serpentine, when it occurs in extensive beds, is a mineral which 
has nearly the same chemical composition, generally known by the name of soapstone. This 
is particularly the case in the counties of Richmond and St. Lawrence. In consequence of 
its softness and tenacity, soapstone may be turned or cut into articles of various shapes, and 
rendered hard by exposure to heat. It is hence much used for the hearths of furnaces, the 
sides of fireplaces, the linings of stoves, and for other similar purposes. 
Another substance often found with these magnesian minerals, is asbestus, under which I 
include the variety composed of flexible silky fibres, sometimes .known by the name of amian¬ 
thus, there being no line of specific distinction to warrant its separation. This mineral has 
* Should the preparation of these salts of magnesia become important, the dolomites or double carbonates of lime and magnesia 
which occur at Sing-Sing and elsewhere, may be also advantageously employed for that purpose. The double carbonate is first 
to be calcined, and then treated by sulphuric acid or sulphate of iron. There is thus formed an insoluble sulphate of lime and a 
soluble sulphate of magnesia, which can be easily separated, 
f Emmons. New-York Geological Reports, 1838. 
