Andradite
is a member of the Garnet Group of minerals that includes
Almandine, Andradite, Grossular, Pyrope, Spessartine and Uvarovite.
Andradite's various colors include yellow,
greenish yellow to emerald-green, dark green, brown,
brownish Red, brownish Yellow; grayish black and black.
Andradite is found in several varieties including Demantoid, Melanite and
Topazolite.
Demantoids are the rich green variety colored by chromium
and are the best known of the Andradites. Demantoid
is named from the archaic German word "demant" which
means "diamond" in allusion to its very high brilliance resembling that of
Diamond. Melanites are typically black
and contain about 1-5% titanium oxide. Melanite
is named from the Greek word "melan", meaning
black. Topazolites are a rare yellow to golden yellow
variety named for its resemblance in
color and clarity to Topaz.
Andradite was named in
1868 by American geologist
and mineralogist James Dwight Dana (1813-1895)
in honor of José Bonifácio de Andrada e Silva (1763-1838), Brazilian mineralogist
who first described the mineral.
José Bonifácio was a mineralogist,
naturalist, poet and professor of geology. He discovered
and named four new mineral species: Cryolite, Petalite,
Scapolite and Spodumen. He also named these eight mineral
varieties (or synonyms): Acanthicone
(syn. of Epidote), Allochroite (syn. of Andradite),
Aphrizite (a black variety of Tourmaline), Coccolite (syn. of Diopside), Ichtyophtalme
(syn. of Apophyllite), Indicolite (blue variety of Tourmaline),Salite
(variety of pyroxene) and Wernerite.
José Bonifácio named most of the minerals
which he discovered with scientific names derived from
Greek words, with the exception of Wernerite. Wenerite
was named in 1800 by José Bonifácio to
honor
Abraham Gottlob Werner (1749-1817), a professor of mining and mineralogy at the Freiberg Mining Academy,
Germany. Werner
was an influential teacher and his ideas shaped early geological
thought. He has been called the "father of German geology". In
September 1792, José Bonifácio went
to Germany to attend the Frieberg Mining Academy to study under Werner.
Distribution:
widespread; fine examples from; in Italy, at Frascati,
Alban Hills, Lazio; the Val Malenco, Lombardy; the Ala
Valley, Piedmont; and Larcinaz, Val d'Aosta. At Dognecea
(Dognaczka) and Oravi»ta (Oravicza), Banat, Romania.
From Ocna de fier, Romania (Vaskö, Hungary). At Zermatt,
Valais, Switzerland. From Arendal, Norway. In the Wessels
mine, near Kuruman, Cape Province, South Africa. In
Russia, gem crystals from the Bobrovka River, Nizhni
Tagil district, and the Sissertsk district, Ural Mountains;
at Sineretschenskoje, north of Vladivostock. In the
USA, from Stanley Butte, Graham County, Arizona; on
Garnet Hill, Calaveras County, and around the Gem mine,
San Benito County, California; at Franklin and Sterling
Hill, Sussex County, New Jersey; from Magnet Cove, Hot
Spring County, Arkansas; and on Prince of Wales Island,
Alaska. In Mexico, found near Charco de Peña, about
75 km east of Lázaro Cárdenas, Chihuahua.
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