404 
DESCRIPTIVE MINERALOGY. 
ness from 5.5 to 6.0. Specific gravity from 3.82 to 4.06. Before the blowpipe on charcoal, 
it fuses with slight intumescence into a black globule, which is strongly attracted by the mag¬ 
net, if not heated to redness ; with borax, it melts into a dark green and almost opaque glass. 
It forms a jelly with heated muriatic acid. 
Composition. Protoxide of iron 52.54, silica 29.28, lime 13.78, oxide of manganese 
1.59, alumina 0.61, water 1.27 (Stromeyer). 
Geological Situation. The principal locality of this mineral is the island of Elba, where 
it is found associated with epidote, garnet and iron ore, in limestone. It has also been met 
with in Norway and Siberia. 
LOCALITIES. 
According to Dr. Emmons, this species occurs in Essex county ;* but I am not acquainted 
with the precise locality, nor can I give any further account of it. 
Ilvaite or yenite, according to Shepard, has been found at Cumberland, Rhode-Island, in 
slender crystals in quartz, associated with hornblende and magnetic iron ore. 
SILICATE OF IRON. 
Description. In the slag from the furnace for the cementation of steel, at Ramapo in 
Rockland county, there are often found cavities lined with short four and six-sided prisms 
with dihedral summits, as in Fig. 479. They have an iron black colour and metallic lustre, 
slightly magnetic. Easily fusible by the blowpipe into a bright iron-blue globule, which is 
attracted by the magnet. 
Composition. Protoxide of iron 70.00, silica 30.00. It is therefore a silicate of iron: 
Fe0.Si0 3 . 
This mineral has the same composition as the anhydrous silicate 
of iron of Thomson, but the latter is said to be infusible by the 
blowpipe. It is, however, exactly similar to the artificial silicate 
described by Mitscherlich as formed during the refining process of 
cast iron, and which has the crystalline form of peridot, Fig. 479, 
The primary being a right rectangular prism.t T on n 114° 6 '; 
T on k 138° 31k 
The same product is noticed by Beudant, under the name of 
peridot with a base of iron4 
* New-York Geological Reports. 1839. 
| Brewster's Edinburgh Journal of Science. II. 129. — In this paper, Prof. Mitscherlich notices the occurrence of scoriae at. 
Fahlun and Garpenberg in Sweden, and in several of the foundries of Germany, possessing the same form and composed of 
the same elements as certain minerals found in nature, 
t Traite des Essais par la Voie Seche. I. 445. 
Fig. 479. 
