Hematite color

Oceanic zooplankton species, wax esters in, 26 204-205 Ocean ranching, 3 198 Ocean raw materials, 17 684-699 consolidated deposits of, 17 691-694 economic aspects of, 17 697 fluid deposits of, 17 694-695 minerals recovery from, 17 695—697 unconsolidated deposits of, 17 686-691 Ocean resources, global, 17 684—686 Oceans, selenium content of, 22 11. See also Marine entries Seawater Ocean thermal energy conversion (OTEC) power plants, 13 267, 268 26 92-93 Ocean transportation, 25 328 Ochratoxin A, 7 267-268 Ochre (mineral hematite) color, 7 333... 

Iron Oxides. In addition to the black iron oxide, there are several natural and synthetic yellow, brown, and red oxides. As a class, they provide inexpensive but dull, lightfast, chemically resistant, and nontoxic colors. The natural products ate known as ocher, sieima, umber, hematite, and limonite. These include varying amounts of several impurities in particular, the umbers contain manganese. Their use is limited because of low chroma, low tinting strength, and poor gloss retention. 

Figure 7.11 Smooth attack on carbon steel by carbonic acid. Note the vivid red color of hematite, indicating high oxygen concentrations.

Copper salts usually are the result of corrosion in the post-boiler section and may be present as red cuprous oxide (Cu20), black cupric oxide (CuO), or blue-green copper sulfate (CuSO ). Mostly, copper salts are mixed with hematite and magnetite and take on a black color. 

Ordinary rust typically is primarily non-ferromagnetic Fe203 (ferric oxide, or hematite). It is often red in color and can be found variously as a light and fluffy material or as a hard and dense tubercle or other type of deposit. 

The most common ore of iron is hematite that appears as black sand on beaches or black seams when exposed in the ground. Iron ores (ferric oxides) also vary in color from brownish-red to brick red to cherry red with a metallic shine. Small amounts of iron and iron alloys with nickel and cobalt were found in meteorites (siderite) by early humans. This limited supply was used to shape tools and crude weapons. 

Barron, V. Torrent, J. (1984) Influence of aluminum substitution on the color of synthetic hematites. Clays Clay Min. 32 157-158 Barron, V. Torrent, J. (1986) Use of the Ku-belka-Munk theory to study the influence of iron oxides on soil colour. Soil Sci. 37 499-510... 

Judd, D.B. Wyszecki, G. (1975) Color in business, science and industry. J. Wiley, New York Jurinak, J.J. (1964) Interaction of water with iron and titanium oxide surfaces Goethite, hematite, and anatase. J. Colloid Sci. 19 477-487... 

D.G. (1986) Relationship among derivative spectroscopy, color, crystallite dimensions and A1 substitution of synthetic goethites and hematites. Clays Clay Min. 34 625-634 Kosowski, B.M. (1993) Nanometer sized iron oxide. Paper presented at Iron oxides in colorant and chemical application". Intertec Conferences. Washington, D.C. 

Torrent, J. Schwertmann, U. (1987) Influence of hematite on the color of red beds. J. Sediment. Petrology 57 682-686 Torrent, J. (1987) Rapid and slow phosphate sorption by Mediterranean soils effect of iron oxides. Soil Sci. Soc. Am. J. 51 78-82 Torrent, J. (1991) Activation energy of the slow reaction between phosphate and goethites of different morphology. Aust. J. Soil Res. 29 69-74... 

Iron (III) oxide exists in mineral form as hematite. It is 70% iron and is the primary source of iron ore in the world. About 90% of the iron mined in the United States is hematite. World production of this ore is more than 1 billion tons. Magnetite and taconite are two other primary iron oxide minerals used as iron ore. The name hematite comes from the blood-red color of powdered hematite. The Greek word hematite means blood-like. Some ancients held the belief that hematite was formed in areas where batdes were fought and blood was spilled into the earth. Large deposits of hematite have been identified on Mars. 

Iron(III) oxide crystallizes independently of the synthesis route in the a-modification (hematite) after calcination. Brilliant, intense colors are obtained with 50-250 nm layers of Fe203. Absorption and interference colors are formed simultaneously and vary with layer thickness of iron oxide. Especially, the red shades are extremely intensive because interference and absorption enhance each other (Fig. 79). It is possible to produce an intense green-red flop with different viewing angles at a layer thickness similar to a green interference [5.228]. 

Emery is a mixture of granular corundum of dark color, magnetite and hematite, sometimes with spinel. Quartz may be present For a long time emery was supposed to be an ore of iron. Until the introduction of artificial abrasives, emery was much used for such purposes. 

The most prominent pigments that were used prehistorically are the iron-oxide pigments, often referred to as ochre . While the term is used widely, it is also very problematic. In the strictest sense, it only denotes the color it produces, even though it is often used interchangeably with hematite (Fe ). In fact, the term ochre does not describe any elemental or mineralogical composition, which can vary greatly and in some cases, the ochre-colored material that is described does not contain measurable amounts of iron. 

Commercially sold rabbit hair (Joseph Galler Inc.) and milkweed fibers that had been collected by the researcher in 2004 were each colored with aqueous solutions of lab grade hematite (Fe203) as a substitute for ochre and copper sulfate. Additionally, rabbit hair from a breeder (Jennings, T.), commercially produced rabbit yam, and milkweed fibers were also colored in an aqueous bloodroot dye bath that did not contain any dyeing aids. 

Lab grade hematite (Fe203) and copper sulfate (anhydrous and hydrated) were mounted on slides and used as controls to compare to mineral deposits that might have been found adhering to foe fibers. Rabbit hair and milkweed that had been colored with an aqueous hematite solution and with an aqueous copper sulfate (blue vitriol) solution were also used for comparison. Fibers removed from each simulated material were mounted in water (Refractive Index (Rl) of 1.0), and in Permount (Fisher Scientific) (RI of 1.55). The collected particulate matter and fibers removed from foe yam samples were similarly mounted and examined using optical microscopy. 

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