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8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
E : With only medium-sized cations, (OH, etc.):RO4 > 2:1
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Crystal
Habit:
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As
crystals, short prismatic on [001], {210} rounded, also
showing large {021}, {221}, with a number of other forms
known, to 1 cm; as flat radial aggregates and crusts.
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Common
Associations: |
Copper,
Brochantite, Pseudomalachite, Libethenite, Malachite,
Atacamite, Chrysocolla, Heterogenite. |
Type
Locality: |
L'Etoile du Congo Mine
(Star of the Congo Mine; Kalukuluku Mine), Lubumbashi (Elizabethville),
Southern area, Katanga Copper Crescent, Katanga (Shaba), Democratic
Republic of Congo (Zaïre) |
Cornetite
is a rare secondary copper mineral that is an attractive
deep blue to green-blue color. Crystals are very small
and typically found as flat radial aggregates and crusts.
A faceted gem would be a true rarity. Mineral specimens
have been cut as cabochons for gem collectors.
Cornetite
is found in several notable localities including from
the Star of the Congo mine, near Lubumbashi, and at
the Kalabi and Lukini mines, Katanga Province, Congo
(Shaba Province, Zaire). From the Bwana Mkubwa mine,
Ndola, and Kansanshi, Zambia. At the Alaska, Mangula,
and Molly mines, Lomagundi district, Zimbabwe. In the
USA, in the Blue Jay and Empire-Nevada mines, Yerington
district, Lyon County, Nevada; at Tyrone, Santa Rita,
Grant County, New Mexico; on Saginaw Hill, Pima County,
Arizona. From Cerro Verde, Sonora, Mexico. In Chile,
at Chuquicamata, Antofagasta; the Manto Ruso mine, about
85 km north of Copiapó, Atacama; and the Brillador mine,
La Serena, near Coquimbo. From the Blockade mine, 60
km east of Mount Isa, and at Ravenswood, Queensland,
Australia.
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