Refractive
Index: |
R1–R2:
(400) 58.1–64.2, (420) 58.4–64.8, (440) 58.7–65.3, (460)
59.1–65.7, (480) 59.3–66.1, (500) 59.7–66.5, (520) 60.0–66.8,
(540) 60.1–67.0, (560) 60.2–66.8, (580) 60.0–66.6, (600)
59.5–66.0, (620) 58.8–65.2, (640) 57.9–64.3, (660) 57.1–63.4,
(680) 56.1–62.3, (700) 55.0–61.3
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Tellurium
is a chemical element similar to Copper,
Silver and
Gold. Crystalline Tellurium has a silvery-white appearance with a metallic lustre when pure.
It resists oxidation by air and is nonvolatile.
Tellurium is mildly toxic and people exposed to even
very
small amounts of it in air, develop "tellurium breath", which has a garlic-like odor.
Tellurium is one of the rarest stable solid elements in the Earth's crust
with an abundance comparable to that of Platinum.
The picture above is a gem of Quartz
matrix with
bright, metallic native Tellurium crystals from the
Bambolla Mine, Moctezuma, Mun. de Moctezuma, Sonora, Mexico.
Native Tellurium is often associated with white to yellow
Tellurite and grayish-white to creamy yellow Paratellurite
which are both Tellurium Oxide minerals.
Tellurium was discovered in
1783 by Australian mineralogist Baron Franz Joseph Müller von Reichenstein (1740
or 1742-1825 or 1826) in Gold ore samples from the Mariahilf Mine,
Fata Băii, Zlatna, Transylvania, Romania. Müller
isolated an unknown metal from the samples but after
three years and more than fifty tests he could not identify
it. Apparently in frustration, he gave it the names aurum paradoxium and metallum problematicum.
Müller sent a sample to German chemist Martin Heinrich
Klaproth (1743-1817) who was able to identify the unknown
metal as a new element in 1798. He named it tellurium from the Latin name of planet Earth, tellus,
and credited Müller with its discovery.
Tellurium
distribution: in
Romania, from Faţa Bâii (Zlatna, Faczebaj) [TL]
and Baia-de-Aries (Offenbánya). At the Fossa
volcano, Vulcano, Lipari Islands, Italy. From the Tolbachik
fissure volcano, Kamchatka Peninsula, Russia. Large
cleavages at the Kochbulak gold deposit, Chatkal-Kuramin
Mountains, eastern Uzbekistan. In the USA, from many
localities in Colorado, including Cripple Creek, Teller
County; in the Magnolia, Gold Hill, Ballarat, and Central
districts, Boulder County; and at the Vulcan mine, Gunnison
County; in Nevada, at the Mohawk and Clermont mines,
Goldfield district, Humboldt County, and from Delamar,
Lincoln County At the Moctezuma (Bambolla) mine, 12
km south of Moctezuma, Sonora, Mexico. From the El Indio
mine, east of La Serena, Coquimbo, Chile. At Kalgoorlie,
Western Australia. In the Teine mine, northwest of Sapporo,
Hokkaido, and in the Kawazu mine, near Sizewka, Shizuoka
Prefecture, Japan. From the Emperor mine, Vatukoula,
Viti Levu, Fiji Islands. At the Guilaizhuang gold deposit,
Shandong Province, and in the Dashuigou tellurium deposit,
Sichuan Province, China. Additional minor localities
are known.
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