HYDROUS PEROXIDE OF IRON. 
29 
HYDROUS PEROXIDE OF IRON. Thomson. 
Limonite. Beudant and Shepard. — Brown Oxide of Iron, and Argillaceous Oxide of Iron. Cleaveland. — Rhombokedral 
Iron Ore. Jameson. — Hydrous Oxide of Iron. Phillips. — Rhomboedrisches Eisen-Erz. Mohs. — Brown Iron Ore. 
Dana. (It includes Brown Hematite, Brown Ochre, Umber, Yellow Iron Stone, Brown Clay Iron Stone, and all 
the varieties of Bog Iron Ore.) 
Under the general name of Hydrous Peroxide of Iron, or Limonite, are now included the 
several species and varieties above mentioned ; for the reason, as in the case of the Specular 
Oxide, that all these minerals run into each other in such a manner as to baffle all attempts to 
give distinctive characters. 
Description. Colours various shades of brown, sometimes yellowish. Powder yellowish 
brown. Without action on the magnet. 
Very rarely occurs crystallized; it usually presents stalatitic, botryoidal or mammillary 
forms, having a fibrous structure; also massive, and sometimes earthy. When crystallized, 
the primary form is said to be a right rectangular prism, but its occurrence in crystals has 
been doubted by many mineralogists. 
Hardness, when pure, 4.5 to 5 ; in its impure form, its hardness is very variable. Specific 
gravity 3.922 (Haidinger ); 3.37 to 3.94 ( Beudant ). 
Infusible by the blowpipe, but gives out water by calcination; and most of the varieties 
become black or reddish black, and magnetic. With borax, it melts into a green or yellow 
glass ; and it is soluble in heated nitro-muriatic -acid. 
Composition. Limonite is supposed to be a hydrate of the peroxide of iron, the proportions 
being 85.30 peroxide of iron, and 14.70 of water ; so that in its purest form, 100 parts of the 
ore contain 59.70 metallic iron. There are, however, generally found in it various other 
substances, either in mixture or in combination; as silica, alumina, oxide of manganese, and 
some ore of zinc. Titanium is also occasionally associated with it. It is sometimes mistaken 
for the oxide of manganese, but the chemical characters are sufficiently distinctive. 
This mineral is here very widely and abundantly diffused. It is one of the most important 
of our ores, and furnishes a considerable proportion of the iron at present produced in this 
State. 
I shall now notice some of the principal localities of this ore, commencing in the southern 
part of the State, and proceeding towards the north and west. 
Richmond County. Five or six miles southwest of the Quarantine,' on the road to Rich¬ 
mond village, there are beds of brown hematite, of some extent. The ore is sometimes 
massive, and at others consists of spherical grains of various sizes, united by a ferruginous 
cement, and known by the name of shot ore. It often has a shining surface, and appears to 
be mixed and coated with talc. Brown and yellow ochres are also found here, and are used 
by the inhabitants as paints. 
