Wednesday, September 1, 2010

Lead vanadate forms Vanadinite, discovered in Mexico

Mine: San Carlos (Mina Apex), San Carlos, Manuel Benavides, Chihuahua Mexico

Vanadinite is an uncommon mineral, only occurring as the result of chemical alterations to a pre-existing material. It is therefore known as a secondary mineral. It is found in arid climates and forms by oxidation of primary lead minerals. Vanadinite is especially found in association with the lead sulfide, galena. Other associated minerals include wulfenite, limonite, and barite.[2][4][5]

It was originally discovered in Mexico by the Spanish mineralogist Andrés Manuel del Río in 1801. He called the mineral "brown lead" and asserted that it contained a new element, which he first named pancromium and later, erythronium. However, he was later led to believe that this was not a new element but merely an impure form of chromium. In 1830, Nils Gabriel Sefström discovered a new element, which he named vanadium. It was later revealed that this was identical to the metal discovered earlier by Andrés Manuel del Río. Del Río's "brown lead" was also rediscovered, in 1838 in Zimapan, Hidalgo, Mexico, and was named vanadinite due its high vanadium content. Other names that have since been given to vanadinite are johnstonite and lead vanadate.

Along with carnotite and roscoelite, vanadinite is one of the main industrial ores of the element vanadium, which can be extracted by roasting and smelting. It is occasionally used as a source of lead. A common process for extracting the vanadium begins with the heating of vanadinite with salt (NaCl) or sodium carbonate (Na2CO3) at about 850°C to produce sodium vanadate (NaVO3). This is dissolved in water and then treated with ammonium chloride to give an orange coloured precipitate of ammonium metavanadate. This is then melted to form a crude form of vanadium pentoxide (V2O5). Reduction of vanadium pentoxide with calcium gives pure vanadium.

Sources: WEikipedia and the University of life!

Monday, May 3, 2010

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Blog award

Saturday, April 17, 2010

I am sad seeing these beauties in women's rings / collars!

In order of appearance:

Tourmalines on Cleavelandite blades from the Himalaya Mine, Mesa Grande District, San Diego County, California

Linarite from the Grand Reef Mine in Graham County, Arizona

Prousite sitting atop a Polybasite cluster from the Uchucchacua Mine, Oyon Province, Lima Department, Peru.

Tourmaline from the 1974 Pocket, Tourmaline Queen Mine, San Diego County, California

Galena from the Tsumeb Mine in Tsumeb, Namibia, SW Africa.

Adamite from the Ojuela mine in Mapimi, Durango Mexico

For sure, these crystals ore from another galaxy!

By order of appearance:

Beryl var. Emerald from a locality near Alabashka, Ural Mountains, Russia

Amazonite crystals with Smoky Quartz and Albite from Sentinel Rock, El Paso County, Colorado

Silver from Imiter Mine in Morocco

Scheelite with fluorite and muscovite from the Mt. Xuebaoding Mine, Pingwu, Sichuan Province of China

Red beryl from the Wah Wah Mountains near Delta, Utah

Mimetite from San Pedro Corralitos, Chihuahua Mexico

Spessartine garnets from Nani, Loliondo, Arusha Region, Tanzania

Sunday, January 24, 2010

More jaw dropping specimens!

Kunzite, Elbaite, Quartz and Albite
Laghman Prov., Afghanistan, Asia

Dow Scar Vein, Hilton Mine
Scordale, Cumbria, England, Europe

Small Miniature
Santa Eulalia
Chihuahua, Mexico

Small Cabinet
Benitoite Gem Mine
San Benito County, California

Los Lamentos
Chihuahua, Mexico