When was hematite discovered

Black, gray to silver gray, brown to reddish brown, red. Some specimens are iridescent , and other are multicolored or banded gray and dark red. Red to reddish brown. Crystal System. Crystal Forms and Aggregates. Crystals occurs in thin plate s, as well as bundles of small micaceous plates, and in thin splinter s. Most commonly massive , mammilary , botryoidal , reniform , oolitic , stalactitic , and radiating.

Scalenohedral and rhombohedral crystals occur, as well as tabular and groups of tabular crystals. Crystals are often striated.

Dendritic and rosette forms are also found. May form as a pseudomorph after other minerals, especially as octahedral crystals of Magnetite. Specific Gravity. Metallic to dull. None, but occasionally exhibits rhombohedral and basal parting. Other ID Marks. Hematite is paramagnetic , meaning it is slightly attracted to magnetic field s.

Complex Tests. Becomes strongly magnetic when heated. In Group. Oxides ; Simple Oxides. Striking Features. Swiss mineral collectors known as stralters work the rugged hills for brilliant, bright black rosettes of hematite. They range in size from under an inch to several inches across, often with bright red rutile crystals sprinkled on shiny black crystal faces. Plus, just a few decades ago, the North Polar region of Russia began to yield superb hematite rosettes very much like the Swiss specimens, along with axinite and gwindel quartz twins.

The huge iron ore deposits of Brazil are also well-known to collectors who prize the superb tabular hematite crystals from Brumado, Novo Horizonte, Itabiria, Con Genar de Campo, and Jaguarcu. Some crystals are pyramidal, scalenohedral, or rhombohedral. In another part of the world, the great iron and copper mines of Cumberland, now Cumbria, England, certainly met the needs of the British Industrial Revolution. Lovely, tiny hematite blades in tight clusters on the matrix are common in this part of the world.

They are often associated with quartz, sometimes with bright red iron oxide inclusions in the quartz crystals. Just as well-known are the large botryoidal masses of hematite to many inches across and pounds in weight. These are actually composed of spherules of hematite needles, which form radiating knobs that interfere with each other to form the undulating smooth surface of mammillary specimens.

Some of these large pieces are covered with tiny, bright specularite hematite crystal blades. Most of these massive hematites are a lustrous black, while still others present as a reddish color to form kidney ore.

Collectors who are in love with the superb rhodochrosite specimens from the Black Rock manganese area of South Africa also enjoy fine prismatic and pyramidal hematite crystals from the Wessels mine, Hotazel. They are lustrous and sharp in well-formed crystals. Farther north is the hematite deposits of Mador Pror, Morocco, where fine bladed crystals are relative newcomers in the mineral market. One of the great classic hematite sources is Elba, Italy, where Napoleon reportedly enjoyed leisure time.

The hematite crystals from this region are hexagonal with slightly curving prism faces. Appearing in interlocking clusters, they sometimes were found penetrating bright pyritohedron pyrite crystals that developed simultaneously with the hematite. The pyrite crystals often exceed several inches across, with hematite crystals in tight interlocking crystals.

Today the hematite and pyrite specimens from the Island of Elba, Italy, are considered classics. Surely, given its many crystal forms, multiple sources, and the impact it has had on civilization, every collector should make hematite a very worthy and often very showy addition to a collection. Varieties include kidney ore, martite pseudomorphs after magnetite , iron rose and specularite specular hematite. While the forms of hematite vary, they all have a rust-red streak.

Hematite is harder than pure iron, but much more brittle. Maghemite is a hematite- and magnetite-related oxide mineral. Huge deposits of hematite are found in banded iron formations.

Gray hematite is typically found in places where there has been standing water or mineral hot springs, such as those in Yellowstone National Park in North America. The mineral can precipitate out of water and collect in layers at the bottom of a lake, spring, or other standing water. Hematite can also occur without water, however, usually as the result of volcanic activity. This discovery provided the first mineral evidence that Mars' history may have included water.

TES geologic map of Mars showing hematite-rich areas in red. To find out what helped produce the hematite - water or volcanic activity - they'll be examining both the form of the hematite and the company it is keeping.

Clays and carbonates would indicate there had been water in the area. If the area had been volcanic, you would expect to see other types of minerals like olivine and pyroxene.