What was the former name of the mineral Scheelite?
No. 1-400. Tenkerg, Chukotka 1,7 x 1,2 x 1,0 cm 
| Formula: CaWO 4 |
| Class: Tungstates |
| Application: collectible and very rare – jewelry stone |
| Investment name: Sheelit |
Features
| Hardness (Mohs Scale) | 4,5-5,0 |
|---|---|
| Density | 5,90-6,12 *6,00 |
| Refraction | 1,915-1,937 * 1,93 |
| Birefringence | 0,016 |
| Variance | 0,038 |
| Color | Yellow, brown, orange, bright orange, white, colorless. |
| Transparency | Transparent to translucent. |
| Forms of selection | Pseudooctahedra; crusts, granular and draining masses; impregnation. |
| Syngonia | Tetragonal. |
| Cleavage | Clear according to (101). |
| Kink | Conchoidal, uneven. |
| double refraction | White. |
| Pleochroism | Dichroism is faint orange. |
| Absorption spectrum lines | Doublet 580*. |
| Luminescence and Chelsea filter | Absent (LW), colorless stones – strong light blue (SW), orange stones – yellowish (SW). |
| Characteristics | Moderate dispersion. High density. Strong light blue fluorescence (SW) is common. Industrially synthesized, any color! Powellite also belongs to the scheelite group. |
| Field | Mexico, USA, Germany, Czech Republic, Austria, Italy, UK, Sweden, Switzerland, South Korea, Australia. |
| Brilliance | Fat to diamond. |
| fragility | Fragile. |
More about scheelitis
Scheelite was named after the discoverer of tungsten, Scheele (KWScheele). Powellite, CaMoO4, is isostructural with scheelite and forms crystal forms similar to scheelite. These two minerals form a series of solid solutions where tungsten in scheelite is replaced by molybdenum in powellite. Powellite fluoresces yellow, while scheelite fluoresces bright blue. If some tungsten in scheelite is replaced by molybdenum, it also fluoresces yellow. Scheelite forms perfect tetragonal dipyramidal crystals that are very similar to octahedra. Such pseudo-octaelric crystals are often complicated by secondary pyramids (at the top of the crystal). Scheelite crystals can be similar to fluorite octahedra. Massive scheelite deposits can be confused with massive quartz, but the fluorescence of scheelite removes all questions. Scheelite has been successfully synthesized since 1963. Scheelite is very popular among collectors. Sheelite was also used to a limited extent in jewelry, but after 1963 the jewelry industry used less expensive synthetic scheelite much more often. Transparent examples of scheelite suitable for cutting, mainly from deposits in Mexico and the United States. Superb, huge scheelite crystals are found in China.
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 | Int: 20 | Int: 45 – (60. 75) – 90 | Int: 50 -(90) -127 to 58,6 ct | 10 – (30. 45) – 63 |
| For 1 g of raw materials | Crystals | Shufts | Rarely available for sale | |
|---|---|---|---|---|
| In Russia | not commonly used | 1 – 80 | virtually absent | infrequently – collection. Kam. |
| Abroad | 10 – (15. 20) – 100 | 20 – 1.150 (Int) | Int: 50 -1.445; friends.50 -2.250 | very popular collection Kam. |
Origin of the name: Scheelite is named after the Swedish pharmacist Karl Wilhelm Scheele (1742-1786), who obtained tungsten anhydride from tungstenite (current scheelite) in 1781. In fact, Scheele discovered the new element tungsten without isolating it as a metal. Other names (synonyms): Tungstein, tungstenite, trimontite, scheelspar Types of mineral: Cuprous scheelite – with copper oxide content up to 7%.
Sample photos
Sheelit
Sample size: 5,4h5,0h3,5 see Photo upload date: 2012-07-30
Materials
Syngony: Tetragonal Composition (formula): CaWO4, a typical admixture of molybdenum: scheelite forms a solid solution with powellite CaMoO4 Gray, yellow, greenish-yellow, brown, orange, rarely colorless Trait Color (Powder Color): White
Transparency: Transparent, Translucent
Cleavage: Medium
Fracture: Uneven, Conchoidal, Stepped
Gloss: Diamond, Bold
Hardness: 4,5-5
Specific gravity, g/cm 3 : 5,8-6,2
Special features: Scheelite has blue luminescence. It decomposes in hydrochloric and nitric acid, releasing yellow tungstic acid, soluble in ammonia. A solution in hydrochloric acid when boiled with tin takes on a bright blue color.
Selection form
Scheelite crystals are pseudooctahedral in appearance, sometimes tabular. Hatching is sometimes observed on the edges. Doubles are often encountered. Most often, scheelite is observed in the form of grains and impregnations of irregular shape, continuous masses.
Main diagnostic signs
Scheelite in crystals is recognized by its pseudo-octahedral appearance, in aggregates – by its greasy, rather strong luster, relatively low hardness, noticeable cleavage, high specific gravity, and reaction to tungsten. One of the main diagnostic properties of scheelite is its bluish-white luminescence.
Related Minerals
Origin
Most often, scheelite is found in contact-metasomatic deposits: skarns, greisens. Sheelite is often observed in hydrothermal vein deposits of tungsten and gold. Small quantities of scheelite are sometimes found in pegmatites. Under surface conditions, scheelite is not completely stable, however, quite often scheelite can be found in the heavy fraction of concentrates.
Deposits/occurrences
In Russia Well-known deposits of scheelite are Tyrnyauz (Kabardino-Balkaria), Buranovskoye (Chelyabinsk region), Boevskoye (Sverdlovsk region). Shelite is noted in skarns and quartz veins of the Kheposelkya occurrence (Northern Ladoga region). Large crystals were found at the Tenkergyn deposit (Chukotka).
Foreign deposits of scheelite: Maykhura (Tajikistan), Kramat-Pulai (Malaysia). Many deposits are known in the western states of the USA, Canada, and the island of Tasmania. The oldest deposits are in the Ore Mountains of Germany, the Czech Republic, and Austria.
Application
Scheelite ores serve as a source of tungsten. Tungsten is primarily used in the iron and steel industry to produce special grades of hard steel. In addition, tungsten is part of alloys with chromium, cobalt and other metals, which are superhard alloys: victorious, stalinite, visible, etc. These alloys are used for the manufacture of special bits for drilling wells. Tungsten is used to make filaments in electric lamps and anticathodes in X-ray tubes. In the chemical industry, tungsten compounds are used to color glass and porcelain. Tungsten sulfide is used as a high temperature lubricant.
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