Spinels (oxides): Chromite

Diagnostic card.
On the picture. Rare crystals of chromite from Rio-Crevés (Italy)

Fe Cr ₂ O ₄
Cubic cubic system
Hardness 5,5
Specific weight 4,5-4,8
Cleavage is absent
Fracture irregular, shell
Black color
Color in powder brown
Glitter semimetallic

Chromite (chromite ironseed), - iron and chromium oxide with permanent impurities Mg, Al, sometimes Ti, Mn, V. Metallic shine, opaque. Color black, brownish-black. The dash is brown. The fracture is conchoidal, brittle. Cleavage is absent. Chromite deposits are genetically associated with ultrabasic magmatic rocks (dunites, etc.). Crystals (cubic syngony) are rare, more often dense, granular masses. The most important ore is chromium. Deposits: in Turkey, Greece, CIS, Zimbabwe, Cuba, South Africa.

Named for the chemical element contained in it. A typical mineral of ultramafic igneous rocks. Chromite is an oxide of iron and chromium. If it does not contain other elements, the chromium content is more than 50%. In fact, it almost always contains some magnesium and aluminum. The mineral crystallizes in cubic syngony; But its spectacular crystals (usually small octahedra, black and opaque) are extremely rare. Basically, there are massive granular clusters. The gloss is semimetallic, the color in the powder is brown. Cleavage is absent, the mineral is brittle, hard, heavy.

Diagnostic signs.
The brown color in the powder and the fact that chromite exhibits weak magnetic properties makes it possible to distinguish it from magnetite. At the latter, moreover, the color of the powder is black, and its dust particles are easily attracted by a magnet.

Origin.
Chromite is characteristic of a number of magmatic intrusive rocks rich in olivine. These are peridotites and dunites, which are separated from the main magma in the early stages of its crystallization. This phenomenon was called "magmatic segregation." Chromite is also found in serpentinized rocks formed due to the transformation of igneous rocks. In addition, as a result of weathering and destruction of chromite-bearing rocks, the mineral can accumulate in alluvial deposits, so-called placers.

Place of Birth.
Large deposits are being actively developed in Turkey, South Africa, Zimbabwe and the Philippines. Finally, the extraction of chromite occurs in Macedonia and Albania (Kukosh zone).

Application.
Chromite is the main ore mineral for the production of chromium, which is necessary primarily for the manufacture of certain stainless steels and hard alloys used in the processing of metals, which implies the presence of signs such as gloss, polishing, and non-adherence to corrosion.

Lame. Ural, Russia. Photo: © А.А. Evseev.

Chromium is a vital element, which in the human body activates enzymes involved in the metabolism of carbohydrates; In the synthesis of fatty acids, cholesterol and proteins (they are composed of the human body). Chromium regulates blood sugar levels, increases insulin activity, people with high chromium levels in the body are less likely to develop diabetes and atherosclerosis. Affects the processes of hematopoiesis and fat splitting, promotes the resorption of atherosclerotic plaques (acrylic), reduces cholesterol on the walls of the aorta, protects the myocardial proteins from destruction. A stock of chromium helps to overcome stress.

The level of chromium decreases in women during pregnancy and after the birth of a child. This deficiency of chromium can explain the diabetes of pregnant women, although this reason is hardly the only one. Chromium deficiency in the body, in addition to increasing the level of glucose in the blood, leads to an increase in the concentration of triglycerides and cholesterol in the blood plasma and, finally, to atherosclerosis. In the body, chromium compounds come with food, water and air.

The bioavailability of chromium from inorganic compounds in the gastrointestinal tract is low, only 0.5-1%, but it increases to 20-25% when chromium is introduced as complex compounds (picolinate, asparaginate). Hexavalent chromium is digested in 3-5 times better than trivalent. Dietary factors affect the bioavailability of chromium. Thus, the absorption of chromium increases in the presence of oxalates and decreases with iron deficiency. The absorption is influenced by physiological factors, for example, load or aging.

Chromium increases muscle tone, performance and physical strength. He helps athletics and bodybuilding enthusiasts build muscle (the volume of the cell, keep water in the body) and improve strength endurance. The lack of chromium leads to growth retardation, causes neuropathy and impairment of higher nervous activity (brain), reduces the fertilizing capacity of spermatozoa (in men). Abuse of sugar increases the need for chrome and its loss with urine. Zinc and iron in the form of chelating compounds can act as synergists of chromium. Chromium is necessary: ​​for diabetes, obesity, osteoporosis, hyperlipidemia, atherosclerosis.

Symptoms of chromium deficiency. The state of anxiety, fatigue, insomnia, headaches, fatigue, neuralgia and decreased limb sensitivity, impaired muscle coordination, trembling in the extremities, intolerance to glucose (especially in diabetic and middle-aged and elderly people), changes in blood glucose (hyperglycemia, Hypoglycemia), an increased risk of developing diabetes, inferior amino acid metabolism, increased cholesterol and triglycerides in the blood (increased risk of atherosclerosis), increased risk of coronary heart disease, weight loss (weight loss, obesity), reproductive harm in men. Now the deficit of chromium is quite common. Chromium deficiency can develop in people consuming diets high in simple carbohydrates (mental brain work, computer work).

Chromium affects lipid metabolism, causing the splitting of excess fat in the body, which leads to normalization of body weight and prevents obesity. The influence of chromium on lipid metabolism is also mediated by its regulatory action on the functioning of insulin. Given the foregoing, chromium is of great importance for the prevention of diabetes, obesity and cardiovascular diseases. Chromium increases muscle tone, performance and physical strength. He helps fans of weightlifting and bodybuilding to build muscle and improve strength endurance.

Chromium is necessary: ​​for diabetes, obesity, osteoporosis, hyperlipidemia, atherosclerosis. The lack of chromium leads to growth retardation, causes neuropathy and impairment of higher nervous activity (nervous activity of nerve trunks from the brain), reduces the fertilizing capacity of spermatozoa. It should be emphasized that the abuse of sugar increases the need for chrome and its loss with urine. With chromium deficiency, the ability to incorporate 4 amino acids (glycine, serine, methionine and aminobutyric acid) into the cardiac muscle is impaired.

Excess chrome in the body can lead to a significant violation of human health. Despite the fact that chromium is a vital element, with excessive intake of human body chromium compounds are highly toxic. The main manifestations of excess chromium: inflammatory diseases with a tendency to defeat the mucous membranes (perforation of the nasal septum), allergic diseases, in particular asthmatic bronchitis, bronchial asthma; Dermatitis and eczema; Astheno-neurotic disorders, increased risk of cancer.

In the form of a natural complex, chromium is present in brewer's yeast, and in this form it is absorbed almost completely. At oral intake in the form of a mineral salt it is acquired only on 3%. The catalyst for the splitting of sugar (brain fuel), the lack of chromium in the body is a disease of workers of intellectual work. The absorption of chromium increases with oxalates and decreases with iron deficiency. Assimilated chromium is excreted from the body through the kidneys (80%) and to a lesser extent through the lungs, skin and intestines (about 19%). Absorbed inorganic trivalent chromium is excreted by the kidneys, in small amounts - with falling out hair, then bile. Large amounts of chromium can be lost with bile.

Food sources of chromium: beer, brewer's yeast; Cheese, dairy products; Meat, veal liver; Eggs; Mushrooms (champignons, white mushrooms, oyster mushrooms, chanterelles, maslata, honey agarics); Vegetables: potatoes (especially - with skin), white cabbage, hot pepper (chili), sweet pepper, radish, beets, tomatoes, Jerusalem artichoke, garlic; Greens: spring onion, chives, parsley, rhubarb (petioles), rucola, dill, garlic greens, spinach; Legumes and cereals: beans, peas, corn, oats, millet, soft wheat, hard wheat, rye and other whole grains, beans, lentils, barley; black pepper; Fruits: quince, pineapple, cherries, figs, viburnum, sea-buckthorn, peaches, feijoa, persimmon, cherry, blueberry, mulberry; Dried fruits: raisins, figs dried, dried apricots, dates, prunes; Nuts and seeds: peanuts, sesame, poppy, macadamia, almonds, Brazilian nut, cedar nut, pumpkin seeds (garbuz), pistachios, hazelnuts (hazelnut); Vegetable oils: corn oil, olive oil; Red algae (on cinnabar). In the form of a natural complex, chromium is present in brewer's yeast, and in this form it is absorbed almost completely. At oral intake in the form of a mineral salt it is acquired on 3%. To reduce chromium deficiency, sugar, carbonated beverages, sweets, refined white flour products, dry flakes, sweetened with sugar substitutes should not be consumed. With excess consumption of sugar, chromium loss in urine increases, and the need for it increases.

ADR 5.1
Substances that are oxidized
Risk of violent reaction, ignition or explosion if exposed to flammable or flammable substances
Do not allow the formation of a mixture of cargo with flammable or combustible substances (eg sawdust)
Yellow diamond, ADR number, black flame above the circle

ADR 8
Corrosive (corrosive) substances
Risk of burns from skin corrosion. They can react violently with each other (components), with water and other substances. The substance that spilled / crumbled can emit a corrosive vapor.
Dangerous to aquatic environment or sewer system
White upper half of diamond, black - lower, equal, ADR number, test tubes, hands