Stones by zodiac signs

What metal is included in magnesite?

No. 1-199. Brazil Weight 9,27 carats

Formula: MgCO 3, magnesium carbonate.
Class: Carbonate
Group: Calcite
Application: collectible and very rare – jewelry stone
Investment name: Магнезит

Features

Hardness (Mohs Scale) 3,5-4,5
Density 2,90-3,12
Refraction 1,515-1,717
Birefringence 0,202
Variance No
Color Yellowish, grayish to pure white, brownish, less often colorless.
Transparency Transparent to opaque.
Forms of selection Crystals are rare; dense, different-grained aggregates (up to porcelain-shaped), earthy, are common.
Syngonia Trigonal.
Cleavage Perfect by (1011).
Kink Stepped.
double refraction White.
Pleochroism Absent.
Absorption spectrum lines Doesn’t interpret.
Luminescence and Chelsea filter Absent.
Characteristics The doubling of the ribs is very large. Granite for collections. There is no reaction to carbon dioxide in the cold and boils when heated. In the form of natural concretions, they are used for cabochons, and are often painted turquoise.
Field Russia (Ural), Austria, Greece, India, Brazil (Bahia piece – jewelry colorless crystals), USA (California piece – snow-white aggregates).
Brilliance Glassy, ​​dim.
fragility Fragile.

More about magnesite

It got its name from the presence of magnesium in its composition – magnesite is magnesium carbonate MgCO 3. First described by Karsten D in 1808. It occurs in the form of solid masses, less often in the form of crystals. Color white, yellowish, grayish. Magnesite generally does not form good crystals. More often it is formed when magnesium-containing rocks change during low-temperature metamorphism under the influence of carbonate-containing solutions. Magnesite has the same structure as calcite. It is rarely used as a jewelry stone. Pure white samples are processed into cabochons, and stone carving is occasionally used. Rare transparent crystals are cut. Many of the properties of magnesite are either identical or very similar to those of calcite. Magnesium prevents magnesite from reacting quickly (CO3) with cold acids, as in calcite, and this is the most reliable means of separating calcite and magnesite. Another mineral, dolomite (MgCa(CO3)2), is also very difficult to distinguish from magnesite. The cabochon and carving material is snow-white in color but slightly porous and is found in a number of places in California. Recently, this material in the form of natural nodules began to be painted turquoise and an excellent imitation was obtained. Large size clear cutting material comes from pcs. Bahia (Brazil). Some cut crystals weigh 50-100 carats. The Brazilian deposit is the only source of cutting raw materials.

Market prices* for inserts, raw materials and collection stones (in USD) (*indicative)

Faceted inserts (per 1 carat) Gold price ratio
1 carat or less 3-5 carats 10 carats or more
In Russia virtually absent virtually absent virtually absent ——
Abroad 81 (Int) 30 – 45 (Int) Int: 10 – 37 (up to 19 ct) 5 – 40
For 1 g of raw materials Crystals Shufts Rarely available for sale
In Russia 2,4 – 3 $/kg virtually absent virtually absent rarely – opaque. raw materials
Abroad Int: 100 r transparent 36 – 80 (Int) 20 – 125 (Int) collectible material.

Magnesite is a carbonate rock that consists of the mineral of the same name. Chemical formula – MgCO3, magnesium carbonate. The outdated name is magnesium spar. Magnesite received its name in honor of the city of Magnesia (Greece), where it was first discovered. The mineral has been known since ancient times. The color of the stone is white with a grayish, yellowish or pinkish tint, sometimes snow-white, the luster is glassy.

Varieties

  • Amorphous – is a porcelain-like substance of white color.
  • Crystalline – More like coarse-grained marble.

The amorphous variety is also called gelmagnesite or colloidal magnesite.

Based on the presence and quantity of impurities, hoshiite (enriched in nickel) and several types of magnesite enriched in iron are also distinguished: breinnerite, mesitite, pistomesite (contain siderite impurities in different proportions). The double compound of magnesite with calcite (CaCO 3 ×MgCO 3) forms dolomite.

Origin

Most often, magnesite is formed by hydrothermal and metasomatic transformation or weathering of magnesian silicates of ultramafic rocks, but materials of sedimentary origin also occur.

In this case, crystals themselves are rarely formed; usually the mineral is presented in the form of dense aggregates and nodules of complex shape.

Production and drilling

Magnesite deposits are quite extensive. The most famous are in Austria, Slovakia, the Democratic Republic of the Congo, Spain, Brazil, Kazakhstan, and Italy. Promising deposits have been discovered in Cuba, Turkey and the USA.

Extraction of magnesite using a hydraulic drill and a Delta auger

Extraction of magnesite using a hydraulic drill and an Impulse auger

Extraction of magnesite using a Delta auger

In Russia, 78,5% of explored reserves of crystalline magnesite are located in the East Siberian region, but 90% of the production of magnesite raw materials is concentrated in the Urals. This is explained by the inaccessibility of Siberian deposits.

One of the most important sources of magnesite in Russia is the Satka group of deposits. Initially, mining here was carried out by open-pit mining, but later a mine was built. Currently, about 90% of the remaining reserves of the Satka group of fields are intended for underground mining.

As for drilling, magnesite belongs to soil category III according to SNiP IV-2-82. This means that for the job you will need an Impulse, Delta or HammerMaster hydraulic rotator, which can be equipped with either abrasive and rock augers S4 and S5, or abrasive/permafrost augers S6 and PR.

  • Maximum torque, Nm 80
  • Diameter, mm 600
  • Drilling tool type Auger

  • Maximum torque, Nm 30
  • Diameter, mm 600
  • Drilling tool type Auger

  • Base vehicle weight, t 21-50t
  • Torque, Nm 33295-75589
  • Oil flow, l/min 100-280

But dense magnesite is included in the IV category of soils in terms of drillability. For drilling, it will need the same rotators, but more powerful augers – rock S4, abrasive or rock S5, abrasive, permafrost or rock S6 and PR.

Application

Magnesite is an ore for mining magnesium and its salts.

By firing at a temperature of 750-1000°C, caustic magnesia in powder form is obtained from magnesite. Processing at 1500-2000°C produces fireproof magnesia, which contains mainly periclase (magnesium oxide, MgO). Finally, especially pure fused periclase is obtained in electric furnaces with temperatures up to 3000°C.

  • Refractory magnesia is used in large quantities in metallurgy.
  • Caustic magnesia is used in the chemical industry (production of paints, synthetic rubber, fertilizers, etc.).

Magnesite is a valuable raw material for the production of refractory bricks.

Magnesite is also used as an ornamental stone. It is easily painted, so it is often given the appearance of turquoise, coral, lapis lazuli.

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