178 DESCRIPTIONS OF MINERALS. 
and the same is found in Pennsylvania and south to Alabama, 
and also in Wisconsin ; it, contains 50 per cent. of oxide of 
iron, with about 25 of carbonate of lime and more or less 
magnesia and clay. The coal region of Pennsylvania affords 
abundantly the clay iron ores, but they are mostly either the 
argillaceous carbonate or hmonite. 
Valuable as an iron ore, though less easily worked when 
pure and metallic than the magnetic and hydrous ores. Pul- 
verized red hematite is used for polishing metal. Red chalk 
is a well-known material for red pencils. 
IWfenaccanite.—Ilmenite. Titanic Iron. Washingtonite. 
Rhombohedral. RAR=85° 31’. Often in thin plates or 
seams in quartz; also in grains. Crystals sometimes very 
large and tabular. , 
Color iron-black ; streak submetallic. Lustre metallic or 
submetallic. H.=5-6. G.=45-5. Acts slightly on the 
magnetic needle. 
Composition. Like that of hematite, except that part of 
the iron is replaced by titanium; the amount replaced is 
very variable. Infusible alone before the blowpipe. 
Diff. Near specular iron, but its powder is not red. 
Obs. Crystals, an inch or so in diameter, occur in War- 
wick, Amity and Monroe, Orange County, N. Y.; also near 
Edenville and Greenwood Furnace ; also at South Royalston 
and Goshen, Mass. ; at Washington, South Britain, and 
Litchfield, Conn, ; at Westerly, Rhode Island. 
It is of no value in the arts and is a deleterious constitu- 
ent of many iron ores. 
. Magnetite.—Magnetic Iron Ore. 
Isometric. Often in octahedrons (fig. 12), and dodecahe- 
2. 
1 drons (fig. 13). Cleavage octahe- 
dral ; sometimes distinct. Also 
granularly massive. Occasionally 
in dendritic forms between the 
fola of mica. 
Color iron-black. Streak black. 
. Brittles” i= 5°5=6"5. 1G, =- 010 
-5'1. Strongly attracted by the 
magnet, and sometimes having polarity. 
Composition. Fe Fe 0,=Fe 0 + Fe O,- =Oxygen 27:6, iron 

