Oxides and hydroxides: Euxenite

Diagnostic card.

Y (Nb, Ti, Ta) ₂ (O, OH) ₆
Diamond orthogonality
Hardness 5,5-6,5
Specific weight 4,3-5,9
Cracked shell
Color black or light brown
Color in powder brown-yellow, brownish-gray
Glitter metal

Good crystals (tabular or short-prismatic) are rare. Color black, brownish-black, velvety-black, less often greenish-black; Often covered with brownish crusts of products of change and weathering. More dense masses with a typical bright gloss on the surface of the fracture are more common. This mineral is highly radioactive due to the presence of uranium and thorium. He does not belong in private collections!

The composition varies widely, generally responding to the formula AB2O6, A = Y, Yh, Dy, U, Ca, Ce, Th, Pb, (Fe2 +?); B = Nb, Ti, Ta, possibly Fe3 +, Sn; About part replaced by OH. The Ti content is 42-66% of the sum of Ti + Nb + Ta, rarely exceeds 70% (polycrazes are enriched in titanium). Typically, several percent of Ta2O5 is contained; The content of Ta is essentially only in tanteuxenite and, especially, in tantalum-polycraz.

In group A, the main role is played by elements of rare earths (18.5-35.5% TR2O3); Among them, the elements of the yttrium group predominate, whereas the elements of the cerium group are contained in a small amount, their role somewhat increases in enriched tantalum varieties. The uranium content is generally within the range of 4-8% UO2, rarely reaching 14-16%; The amount of ThO2 varies from traces to 6.5%. In addition to Ca, Mg and Mn, Pb is often indicated; Characteristic of the presence of Fe, apparently in the form of both Fe2 + and Fe3 +. The unequal content of Ui and the unequal ratio of the isotopes of Pb in separate parts of the same crystal were noted, which is important for the determination of the absolute age for euxenites. The admixtures of Sc, Zr, Hf, Ge, N, and also B.

Usually partially or completely metamicthen and x-ray amorphen. Nemethactite euxenite is exceptionally rare in nature. The crystals are columnar, somewhat elongated along the c axis, thick or thin-plateated along b (010). Crystals are imperfect, crystal measurements in all cases are only approximate. The edges are always matte; Longitudinal hatching is developed on the faces of the vertical belt, and on the other faces a common shading parallel to the edge with b (010) is also developed. The twins in (201) are common, the pinnate shading on the common face b (010) is typical. We also know twins in (101) and in (111). Frequent subparallel and fan-like intergrowth of crystals. Cleavage is not observed. In thin fragments shines yellow-red or reddish-brown color. Strongly radioactive. Does not luminesce in the ultraviolet rays. The dielectric constant is 3.74-5.29, most often 4,02-4,63.

Diagnostic signs.
Euxenite is relatively easy to distinguish from other minerals in appearance and chemical composition. But it is easily confused with other complex oxides that have a similar composition. The indicator is a simple chemical tests for niobium, and (with a visual study of the sample) association with ilmenite. When heated, it crackes and, like all metamicture minerals, glows. Does not melt. In the close. Tr. Usually emits a little water.

Origin.
Euxenite is a typical mineral of some pegmatites, in which it sometimes occurs in appreciable numbers, in association, primarily with ilmenite, mica and other minerals of rare earths. Solid masses of irregular shape, crystals, grains.

Place of Birth.
The most famous deposit of this mineral is in southern Norway. In addition, he is known in Madagascar (where beautiful crystals are found) and in Brazil.

Germanium (Ge) - a biological substitute for calcium Ca (for biological functions in orgshanizme it is similar). Germanium Ge is a microelement that in the human body increases the effectiveness of the body's immune system, fights against cancer (treatment of bone tumors with radiation), reduces pain. The daily requirement of the human body is 0.4-1.5 mg (provided it is replaced by calcium in the future).

Germanium Ge is radioactive and well absorbed by the body (about 95%) and relatively evenly distributed to organs and tissues (both in extracellular and intracellular spaces). Germanium is excreted from the body mainly with urine (90%). Biological role in the human body. In the human body, organic Ge germanium has a wide spectrum of biological activity:

• Has an antihypoxic effect - provides oxygen transfer to the tissues of the body and, transferring oxygen, prevents the development of oxygen deficiency at the tissue level, reduces the risk of developing the so-called blood hypoxia, resulting from a decrease in hemoglobin in erythrocytes (iron deficiency anemia);
• Stimulates immunity by suppressing the processes of multiplication of microbial cells, activating macrophages and specific immunity cells (replacing silver in microdoses);
• Has antifungal, antiviral and antibacterial properties (stimulates the production of interferon to protect against foreign microorganisms) - replaces gold at the level of microelements;
• Is a powerful antioxidant - a blocker of free radicals in the body;
• Inhibits the development of malignant neoplasms and prevents the appearance of metastases (neutralizes negatively charged tumor particles, thereby suppressing its development - radiation therapy and destruction by radiation of malignant tumors of bones, tendons, serous tissues and fatty deposits);
• Regulates all valve systems of digestion, peristalsis and venous system;
• Reduces pain (germanium compounds stop the movement of electrons in nerve cells, thereby stopping the pain).

Germanium Ge extends the life of laboratory animals by 25-30% (calcium). Synergists and antagonists of germanium Ge. There is information about the synergistic action of germanium and selenium. Signs of the insufficiency of germanium: the development of osteoporosis, increased risk of development of cancer. Insufficient germanium content in the diet is accompanied by damage to the bone matrix. The main signs of excess germanium: skin irritation (on contact with GeCl2, for example, with lignite ash), liver and kidney damage (at very high doses).

Germanium Ge is necessary: ​​for infections of various origins, the general reduced tone of the body, when recovering from a disease, in osteoporosis, the treatment of anemia and immunodeficiency states. Food sources germanium Ge: garlic, garlic, bran, beans, ceps, tomato juice, fish, squid, mussels, shrimp, kelp, milk. Accumulates with age in the human body and is excreted only when the "milk" diet (cheese, sour milk, whey, cottage cheese).

The champion in the content of germanium Ge among food products is garlic (do not warn - usually it is very dangerous in large amounts of dietary supplements). Dry garlic contains 750 μg of Ge germanium per 1 g of dry mass of garlic cloves. It is replaced in the future by calcium (supplementary reception of preparation Ca) - bones with application of germanium become softer, bone tissue is partially replaced by a connective. On the materials: http://www.pharmacognosy.com.ua

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