MAGNESIAN MINERALS. 
57 
e 
MAGNESIAN MINERALS. 
Several minerals are found on Staten Island, and also in other parts of the State, which, in 
consequence of their containing large proportions of magnesia, may properly enough for my 
present purpose be grouped together under the name of magnesian minerals. Some of these 
may be turned to account in the arts. 
The mineral called serpentine constitutes the principal range of hills on Staten Island,'ex¬ 
tending from New-Brighton to a little west of Richmond, a distance of eight miles. It assumes 
a great variety of aspects, from black to nearly white, and from compact to earthy. Some of 
the talcy varieties are commonly known by the name of soapstone. Talc, carbonate of mag¬ 
nesia and hydrate of magnesia abound in it, and the rock might be used with profit in making 
magnesian salts.* 
The suggestion here made in regard to the preparation of magnesian salts from the minerals 
so abundant on Staten Island, is deemed worthy of great consideration. These minerals con¬ 
tain from one third to two thirds of their weight of magnesia, as will be seen from the following 
results of their analysis. 
TABLE 
Showing the composition of several Magnesian Minerals, especially in reference to the 
proportion of Magnesia which they contain, in 100 parts. 
Magnesia. 
Lime. 
Carbonic 
acid. 
Water. 
Silica. 
Protoxide 
of iron. 
Peroxide 
of iron. 
Foreign 
matters, 
and loss. 
1. Hydrate of magnesia,!. 
2. Hydrocarbonate of magnesia,{ 
70.00 
42.41 
. 
3(L82 
30.00 
18.53 
0.57 
0.27 
1.40 
3. Compact carbonate of magnesia ,§ 
44.00 
3.50 
50.00 
_ 
2.00 
0.50 
C & alu- 
4. Magnesite or kerolite,||.. 
41.26 
2.39 
13.50 
41.00 
< mina, 
5. Common serpentine,If.. 
42.16 
1.03 
12.33 
42.26 
1.98 
( 1.85 
No. 1. From Staten Island, and Hoboken, New-Jersey. No. 4. From Staten Island, Stony Point, Rockland Co. etc. 
No. 2 and 3. From the same localities. No. 5. Found in various parts of the State. 
The magnesia contained in either of these minerals would furnish, by combination with 
sulphuric acid, upwards of two hundred parts of sulphate of magnesia or Epsom salts, in the 
form in which it is ordinarily sold in the shops. Moreover, the sulphate of magnesia, thus 
obtained, may be decomposed by carbonate of soda or potash, and produce carbonate of mag- 
* Mather. New-York Geological Reports, 1838. 
X Wachmeister. Silliman's Journal, XVIII. 167. 
II By my analysis. The specimen was from Staten Island. 
Part I. 8 
f Bruce. American Mineralogical Journal, I. 26. 
(j Nuttall. Silliman's Journal, IV. 17. 
11 Thomson. Outlines of Mineralogy, <fc. 
