Hematite103a

HEMATITE:

Hematite has several varieties, each with their own unique names.

Hematite Rose is a circular arrangement of bladed crystals giving the appearance of the flower of a rose. Tiger Iron is a sedimentary deposit of approximately 2.2 billion years old that consists of alternating layers of silver gray hematite and red jasper, chert or even tiger eye quartz. Kidney Ore is the massive botryoidal form and gives the appearance of lumpy kidney-like masses. Oolitic Hematite is a sedimentary formation that has a reddish brown color and an earthy luster and is composed of small rounded grains. Specularite is a micaceous or flaky stone that is sparkling silver gray and sometimes used as an ornamental stone. Hematite is an important ore of iron and its blood red color (in the powdered form) lends itself well to use as a pigment. Hematite gets its name from a Greek word meaning blood-like because of the color of its powder. Ancient superstition held that large deposits of hematite formed from battles that were fought and the subsequent blood that flowed into the ground. Crystals of Hematite are considered rare and are sought after by collectors as are fine Kidney Ore specimens. Hematite is sometimes used in jewelry, either as black reflective stones or as a jewelry piece itself (such as a ring). Some jewelry is marketed as "magnetic hematite". I believe that is more likely another iron oxide, magnetite. The "not really a true mineral" known as Limonite is a mixture of hematite, Goethite, and possibly other similar hydrated oxides and hydroxides. Hematite is a primary component of ordinary rust, but the porousity, softness, and flakyness of rust is likely due to goethite. The beautiful iridescent coating sometimes found on hematite is due to Turgite, still another "not really a" mineral composed of a mixture of hematite and goethite and sometimes described as being a hydrated hematite.

PHYSICAL CHARACTERISTICS: Color is steel or silver gray to black in some forms and red to brown in earthy forms. Sometimes tarnished with iridescent colors when in a hydrated form (called Turgite).

Luster is metallic or dull in earthy and oolitic forms.

Transparency: Crystals are opaque.

Crystal System is trigonal; bar 3 2/m

Crystal Habits include tabular crystals of varying thickness sometimes twinned, micaceous (specular), botryoidal and massive. Also earthy or oolitic.

Cleavage is absent. However, there is a parting on two planes.

Fracture is uneven.

Hardness is 5 - 6

Specific Gravity is 5.3 (slightly above average for metallic minerals)

Streak is blood red to brownish red for earthy forms.

Associated Minerals include jasper (a variety of quartz) in banded iron formations (BIF or Tiger Iron), dipyramidal quartz, rutile, and pyrite among others.

Notable Occurrences especially nice specimens come from England, Mexico, Brazil, Australia and the Lake Superior region.

Best Field Indicators are crystal habit, streak and hardness.

"The Mineral Hematite"

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