Characteristics of hematite
Three Fang system, arh=0.5421nm, alpha =55. 17'; Z=2. Ah=0.5039nm, ch=1.3760nm; Z=6. Corundum type structure. When the substitution of Ti in the component, the volume of the unit cell will increase; and the substitution of Al will reduce the volume of the unit cell. Complex three party partial triangle body crystal class, D3d-3m (L33L23PC). Intact crystals are rare. Common single form: parallel double C, six square column a, rhombohedral R, u, e, six party biconical n. In the crystal surface, there are three sets of stripes parallel to the cross direction and the triangular concave or growth cone. In accordance with the poly twin, in accordance with (0001) for the introduction of double or contact twin. Chang Chengxian is crystalline, plate-like, scaly, granular and crystalline, dense, blocky, oolitic, bean like, kidney like, powder like, and other aggregates.
Steel gray to black iron, often with a light blue tarnish; aphanitic or powder were dark red to bright red. Characteristics of cherry red or reddish brown streak. Metallic luster to semi metallic luster; sometimes dull. No cleavage. Because double crystals can be split and split. Hardness 5~6. Relative density 5.0~5.3. Polarizing microscope: red, orange, yellow. One axis crystal (-), No=2.988, Ne=2.759. The crystal form of ore is usually a plate shape, mainly composed of surface (parallel, double sides) and rhombohedral. The aggregates are diverse in shape: crystalline, flaky, scaly, or blocky in shape; crystalline in a oolitic, renal, powdery, and earthy form. According to the morphological characteristics of hematite, and some of the following names: with metal luster lamellar aggregates, called hematite; with metal luster of fine flake like aggregates, called mica hematite; is called oolitic hematite or reniform oolitic or reniform; powdered hematite called iron ochre.
The chemical composition of hematite is Fe2O3, and crystal is an oxide mineral of three square system. Similar to that of equiaxed magnetic hematite. Crystals are usually plate-like; aggregates are usually flaky, scaly, kidney like, oolitic, blocky, or earthy. A reddish brown, steel gray to black color, streak are cherry red. Metallic to semi metallic luster. Moss hardness 5.5 ~ 6.5, specific gravity 4.9 ~ 5.3. It is iron black, metallic luster, flaky hematite called border iron ore; a steel gray, metallic luster, scaly called mica hematite, Chinese called "cloud" iron; reddish brown earthy luster dim called ochre, Chinese called "Dai zhe", and to "" refers to the ochre hematite.
