Hi to every one My name is Anil Bikram Singh. I am not professional in any but i like learning different things. Adventure activity and researching in some thing makes me feel proud of something. On the way of some research about gemology in have learned and find out some things. You can find something if you are trying to find about gems of Nepal every with some info as far as i know.
Some Nepali Rough Gemstone.
Some Nepali Rough Gemstone.
Dark Smoky Tourmaline
(Dravite)Black Tourmaline
Dravite, also called brown tourmaline, is the sodium magnesium rich tourmaline endmember. Uvite, in comparison, is a calcium magnesium tourmaline. Dravite forms multiple series, with other tourmaline members, including schorl and elbaite.
The name dravite was used for the first time by Gustav Tschermak (1836–1927), Professor of Mineralogy and Petrography at theUniversity of Vienna, in his book Lehrbuch der Mineralogie (published in 1884) for magnesium-rich (and sodium-rich) tourmaline fromUnterdrauburg in the Drava river area, Carinthia, Austro-Hungarian Empire. Today this tourmaline locality (type locality for dravite) at Dravograd (near Dobrova pri Dravogradu), is a part of the Republic of Slovenia. Tschermak gave this tourmaline the name dravite, for the Drava river area, which is the district along the Drava River (in German: Drau, in Latin: Drave) in Austria and Slovenia. The chemical composition which was given by Tschermak in 1884 for this dravite approximately corresponds to the formula NaMg3(Al,Mg)6B3Si6O27(OH), which is in good agreement (except for the OH content) with the endmember formula of dravite as known today.
Dravite varieties include the deep green chromium dravite and the vanadium dravite.
Garnet
Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives.
All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different species are pyrope, almandine, spessartine, grossular (varieties of which are hessonite or cinnamon-stone and tsavorite), uvarovite andandradite. The garnets make up two solid solution series: pyrope-almandine-spessartine and uvarovite-grossular-andradite.
Floride
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes inisometric cubic habit, although octahedral and more complex isometric forms are not uncommon.
Fluorite is a colorful mineral, both in visible and ultraviolet light, and the stone has ornamental and lapidary uses. Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite lenses have low dispersion, so lenses made from it exhibit less chromatic aberration, making them valuable in microscopes and telescopes. Fluorite optics are also usable in the far-ultraviolet range where conventional glasses are too absorbent for use.
Corundum
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| Rough corundum ruby |
Corundum is a crystalline form of aluminium oxide (Al
2O
3) with traces of iron, titanium and chromium. It is a rock-forming mineral. It is one of the naturally transparent materials, but can have different colors when impurities are present. Transparent specimens are used as gems, called ruby if red and padparadscha if pink-orange. All other colors are called sapphire, e.g., "green sapphire" for a green specimen.
2O
3) with traces of iron, titanium and chromium. It is a rock-forming mineral. It is one of the naturally transparent materials, but can have different colors when impurities are present. Transparent specimens are used as gems, called ruby if red and padparadscha if pink-orange. All other colors are called sapphire, e.g., "green sapphire" for a green specimen.
The name "corundum" is derived from Tamil word Kuruvindam or Sanskrit word Kuruvinda meaning ruby.
Because of corundum's hardness (pure corundum is defined to have 9.0 Mohs), it can scratch almost every other mineral. It is commonly used as an abrasive on everything from sandpaper to large machines used in machining metals, plastics, and wood. Someemery is a mix of corundum and other substances, and the mix is less abrasive, with an average Mohs hardness of 8.0.
In addition to its hardness, corundum is unusual for its density of 4.02 g/cm3, which is very high for a transparent mineral composed of the low atomic mass elements aluminium and oxygen.
Aquamarine
Aquamarine (from Latin: aqua marina, "water of the sea") is a blue or cyan variety of beryl. It occurs at most localities which yield ordinary beryl. The gem-gravelplacer deposits of Sri Lanka contain aquamarine. Clear yellow beryl, such as that occurring in Brazil, is sometimes called aquamarine chrysolite. The deep blue version of aquamarine is called maxixe. Maxixe is commonly found in the country of Madagascar. Its color fades to white when exposed to sunlight or is subjected to heat treatment, though the color returns with irradiation.
The pale blue color of aquamarine is attributed to Fe2+. The Fe3+ ions produce golden-yellow color, and when both Fe2+ and Fe3+ are present, the color is a darker blue as in maxixe. Decoloration of maxixe by light or heat thus may be due to the charge transfer between Fe3+ and Fe2+. Dark-blue maxixe color can be produced in green, pink or yellow beryl by irradiating it with high-energy particles (gamma rays, neutrons or even X-rays).
The pale blue color of aquamarine is attributed to Fe2+. The Fe3+ ions produce golden-yellow color, and when both Fe2+ and Fe3+ are present, the color is a darker blue as in maxixe. Decoloration of maxixe by light or heat thus may be due to the charge transfer between Fe3+ and Fe2+. Dark-blue maxixe color can be produced in green, pink or yellow beryl by irradiating it with high-energy particles (gamma rays, neutrons or even X-rays).
Beryl
In geology, beryl is a mineral composed of beryllium aluminium cyclosilicate with the chemical formula Be3Al2(SiO3)6. The hexagonalcrystals of beryl may be very small or range to several meters in size. Terminated crystals are relatively rare. Pure beryl is colorless, but it is frequently tinted by impurities; possible colors are green, blue, yellow, red, and white.
Chalkopyrite
Chalcopyrite (/ˌkælkɵˈpaɪraɪt/ kal-ko-py-ryt) is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has thechemical formula CuFeS2. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black.
On exposure to air, chalcopyrite oxidises to a variety of oxides, hydroxides and sulfates. Associated copper minerals include the sulfides bornite (Cu5FeS4), chalcocite (Cu2S), covellite (CuS), digenite (Cu9S5); carbonates such as malachite and azurite, and rarely oxides such as cuprite (Cu2O). Chalcopyrite is rarely found in association with native copper.
Tremolite
Tremolite is a member of the amphibole group of silicate minerals with composition: ☐Ca2(Mg5.0-4.5Fe2+0.0-0.5)Si8O22(OH)2. Tremolite forms by metamorphism of sediments rich in dolomite and quartz. Tremolite forms a series with actinolite and ferro-actinolite. Puremagnesium tremolite is creamy white, but the color grades to dark green with increasing iron content. It has a hardness on Mohs scaleof 5 to 6. Nephrite, one of the two minerals of the gemstone jade, is a green variety of tremolite.
The fibrous form of tremolite is one of the six recognised types of asbestos. This material is toxic and inhaling the fibers can lead toasbestosis, lung cancer and both pleural and peritoneal mesothelioma. Fibrous tremolite is sometimes found as a contaminant invermiculite, chrysotile (itself a type of asbestos) and talc.
Kyanite
Kyanite, whose name derives from the Greek word kuanos sometimes referred to as "kyanos", meaning deep blue, is a typically bluesilicate mineral, commonly found in aluminium-rich metamorphic pegmatites and/or sedimentary rock. Kyanite in metamorphic rocksgenerally indicates pressures higher than four kilobars. Although potentially stable at lower pressure and low temperature, the activity of water is usually high enough under such conditions that it is replaced by hydrous aluminosilicates such as muscovite, pyrophyllite, or kaolinite. Kyanite is also known as disthene, rhaeticite and cyanite.
Kyanite is a member of the aluminosilicate series, which also includes the polymorph andalusite and the polymorph sillimanite. Kyanite is strongly anisotropic, in that its hardness varies depending on its crystallographic direction. In kyanite, this anisotropism can be considered an identifying characteristic.
At temperatures above 1100 °C kyanite decomposes into mullite and vitreous silica via the following reaction: 3(Al2O3·SiO2) → 3Al2O3·2SiO2 + SiO2. This transformation results in an expansion.
Lepidolite (Lithium Mica)
Lepidolite is a lilac-gray or rose-colored member of the mica group with formula K(Li,Al,Rb)3(Al,Si)4O10(F,OH)2.It is a secondary source of lithium. It is aphyllosilicate mineral and a member of the polylithionite-trilithionite series.
It is associated with other lithium-bearing minerals like spodumene in pegmatite bodies. It is one of the major sources of the rare alkali metals rubidium and caesium. In 1861 Robert Bunsen and Gustav Kirchhoff extracted 150 kg of lepidolite and yielded a few grams of rubidium salts for analysis, and therefore discovered the new element rubidium.
It occurs in granite pegmatites, in some high-temperature quartz veins, greisens and granites. Associated minerals include quartz, feldspar, spodumene, amblygonite,tourmaline, columbite, cassiterite, topaz and beryl.
Magnesite
Magnesite is a mineral with the chemical formula MgCO3 (magnesium carbonate). Mixed crystals of iron II carbonate and magnesite (mixed crystals known as ankerite) possess a layered structure: monolayers of carbonate groups alternate with magnesium monolayers as well as iron II carbonate monolayers. [5] Manganese, cobalt and nickel may also occur in small amounts
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