Hematite is dense and hard, it is the most important ore of iron because of its high iron content and its abundance. The mineral occurs in various habits: steel-gray crystals and coarse-grained varieties with a brilliant metallic luster are known as specular hematite; thin, scaly forms make up micaceous hematite; and crystals in petal-like arrangements are called iron roses. It also occurs as short, black, rhombohedral crystals and may have an iridescent tarnish. The soft, fine-grained, and earthy form of hematite is used as a pigment. Important hematite deposits occur in sedimentary beds or in metamorphosed sediments. A compact variety known as kidney ore has a kidney-shaped surface. A form of ground hematite called rouge is used to polish plate glass and jewelry.

It is black or silver gray, brown to reddish brown or red. There are several varieties. Among them; kidney ore, martite, iron rose. There are different forms, however, all of them have a rust red line. It is harder than pure iron, but it can break quickly.

Mineral Group: Hematite group.

Name: From the Greek for blood, in allusion to its color.

Polymorphism & Series: Dimorphous with maghemite.

Association: Ilmenite, rutile, magnetite (metamorphic and igneous); goethite, siderite, lepidocrocite (sedimentary).

Chemical Properties of Hematite

Chemical Classification Oxide minerals
Chemical Composition Fe2O3

Physical Properties of Hematite

Color Metallic gray, dull to bright red
Streak Bright red to dark red
Luster Metallic to splendent
Cleavage None
Diaphaneity Opaque
Mohs Hardness 6.5
Specific Gravity 5.26
Diagnostic Properties Magnetic after heating
Crystal System Trigonal
Parting Partings on {0001} and {1011} due to twinning. Unique cubic parting in masses and grains at Franklin Mine, Franklin, NJ.
Tenacity Brittle
Fracture Irregular/Uneven, Sub-Conchoidal
Density 5.26 g/cm3 (Measured)    5.255 g/cm3 (Calculated)

Optical Properties of Hematite

  • Hematite under the microscope of xpl
  • Hematite under the microscope of ppl
Type Anisotropic
Anisotropism Distinct
Color / Pleochroism brownish red to yellowish red
Twinning Penetration twins on {0001}, or with {1010} as a composition plane. Frequently exhibits a lamellar twinning on {1011} in polished section
Optic Sign Uniaxial (–)
Birefringence δ = 0.280
Relief Very High

Hematite Occurrence

Large hematite deposits appear in banded iron formation. The thist mineral is water soluble and may appear at the bottom of the water and may also appear in non-aqueous environments, which are related to volcanic events. Clay-sized hematite crystals may also appear as a secondary mineral shaped by soil erosion procedures and, together with other iron oxides or oxyhydroxides containing goethite, are responsible for the red color of the soils that have been weathered in many tropics, historic or other conditions.

Hematite Uses Area

  • It is the main iron ore in the world.
  • It is one of the most important pigment minerals.
  • It is a very dense and inexpensive material that is effective in stopping
  • X-rays and is therefore used for radiation protection around medical and scientific equipment.
  • It is also useful as a ballast for ships.
  • Polishing compounds,
  • Minor gemstone

Distribution

Widespread. Exceptional crystals

  • from Switzerland, as at Fibbia, St. Gotthard, Uri; Binntal, Valais; Cavradi, Tavetsch, Gra¨ubunden; and many other places.
  • At Ocna de Fier (Mor´avicza; Vask˝o), Romania.
  • From Rio Marina, Elba, Italy. At Cleator Moor, Cumbria, England.
  • From Kragerøand Hiassen, Norway.
  • In Brazil, large crystals from Mesa Redonda and Congonhas do Campo, Minas Gerais; at Itabira and in the Brumado mine, Bahia; at Miguel Burnier, Ouro Prˆeto.
  • From the Kuruman district, Cape Province, South Africa.
  • At Nador, Algeria.
  • In the USA, in the Thomas Range, Juab Co., Utah, and near Quartzsite, La Paz Co., Arizona.

References

  • Bonewitz, R. (2012). Rocks and minerals. 2nd ed. London: DK Publishing.
  • Handbookofmineralogy.org. (2019). Handbook of Mineralogy. [online] Available at: http://www.handbookofmineralogy.org [Accessed 4 Mar. 2019].
  • Mindat.org. (2019). Hematite: Mineral information, data and localities.. [online] Available at: https://www.mindat.org/ [Accessed. 2019].

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