Iron stones

Often iron stones have an oolithic texture, i.e. they consist of perfectly rounded bodies, the so-called ooids. Iron oxide ooids are mm to cm in size, hardened and showing concentric Fe accumulations (Plate 15.1), which suggest cyclic precipitation of the Fe oxide. Ghemical point analysis by the electron microprobe indicates enrichment of Ti, P and V in the Fe oxides, whereas Si and Al concentrations are very low (Fig. 15.5). The mode of Fe ooid formation and in particular the need for some mechanical action to produce the perfect rounding has been a matter for discussion for a long time. In principle, both terrestrial and marine formation is possible and it... 

Erosional transport of iron stones may have led to a mechanical concentration of these spherical bodies in alluvial sediments or in marine depressions and caused their breakdown Trummererze). These deposits may be recemented by Fe oxides, predominantly goethite, formed in situ in the interstices. 

Chromite or Chrome Iron Ore, (Chrome Iron Stone) (Chromerz, Chromeisenstein, Chromit or Ferrochrom in Ger), Q O. FeO or Fe2(Cr02)2- This ore, which is the most important commercial source of chromium and and its compds, is not found in nature in pure form but mixed with oxides of A1 and/or Mg. Its color varies from iron-blk to brn-blk or streak dr brn. There are several grades metallurgical, refractory, or chemical av d 4.6 and hardness 5.5. Several methods for production of chromium from chromite are known, such as silicothermic, alumino-thermic electrolytical... 

Schoen (1964) black oolites from Clinton iron stone bed near Clinton, N.Y., U.S.A., corrected for impurities. 

Staffordshire, West Yorkshire, and South Wales, yield an argillaceous iron ore, also known as day iron stone, wrhich contains some 10 per cent, of clay and from 30 to 40 per cent, of metallic iron. The Staffordshire ore has many local names, when found in concretionary... 

A clay iron stone containing some 35 per cent, of iron has been worked from Roman times, if not earlier, in the Weald of Sussex and Kent, charcoal being used as the fuel. 

In Linlithgow and Lanark a clay iron stone occurs, impregnated with some 15 per cent, of carbonaceous matter. It is also found in North Staffordshire and in South Wales, and is known as blackband iron stone. The carbonaceous material present is often sufficient to allow the ore to be calcined without the further addition of fuel. A product containing 50 to 70 per cent, of iron is yielded. 

Cleveland iron stone. Variety of clay iron stone. . ... 

Needle iron stone See Goethite. . An acicular variety. 

Liver-coloured Iron-stone, mined in Franconia, and containing particles of purest Gold. 

LAPIDES GEODES — A Stone containing Earth, of oblong shape, filled with a hard ochrine sand, and rattling when shaken the Stone Chemnicensis, of a ruddy colour, like iron-stone, and containing a moist clay. 

White Metallic Marrow from the same place. Found in iron stones. 

Iron-coloured Pyrites is mentioned by Avicenna. It is found in certain iron mines. The miners call it Iron Stone, not that it is actually such, but is like it. From most of these six species fire can be struck. Some of them are very heavy, and are more adapted for striking fire, as Pliny observes. Some distinguish a special genus of Pyrites, which abounds in fire, and is called Live Pyrites. We may, indeed, deny that there is any other genus. Those species which are dense and compact, as the first two, abound in fire. The looser the texture, the more subtle and the more broken up, the less fire can be elicited. Albertus, though a man wise in his time, makes extraordinary mistakes about... 

In the case of iron, stone furnaces were once built at the site of an ore deposit and fed with charcoal made from nearby trees. 

Meteorites are grouped into three major classes irons, stones and stony-irons. Based on compositional dissimilarities, stony meteorites are subdivided into chondrites and achondrites. Chondrites are the most primitive meteorites based on their near-solar volatile composition and radiometric ages of 4.566 billion years, reflecting their formation during, or shortly after, the birth of the Solar System (5). Within the chondrites, there exists a carbonaceous subclass that contains up to 3 weight-% of organic carbon, a characteristic that contributes to a generally dark appearance. Carbonaceous chondrites themselves are subdivided into CM, Cl, CV and other classes based on a combination of their... 

The chief ores of iron are—1. Clay iron stone, which is a more or less pure carbonate of protoxide, generally containing carbonates of lime and magnesia it accompanies coal beds both in England and in Scotland. 2. Red l ematite, which is pure peroxide or sesqnioxide of iron and brown hematite, which is hydrated peroxide. 3. Black or magnetic oxide of. iron. 

Pigmented scars are also observed in iron, stone, silver and flour-mill employees. Cases of skin pigmentation from the external therapeutic application of iron salts, such as ferrous sulfate and ferric chloride, have been described. Hare (1951) reported red-brown, punctate, perifollicular pigmentation from deposition of iron granules on the forearms of a metal worker employed in pickling metal in hydrochloric acid. The pickling fluid contained iron salts in an acid medium. 

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