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Tenorite
Current inventory:  1 gem
 

Chemistry:  CuO  [Copper Oxide]

Discovered in 1841;   IMA status: Valid (pre-IMA; Grandfathered).
Tenorite is named after Michele Tenore (1780-1861), Professor of Botany, University of Naples and G. Tenore, President of the Naples Academy (Italy).

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/A.05-10

Nickel-Strunz 10th Ed. ID:

4.AB.10

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
A : Metal: Oxygen = 2:1 and 1:1
B : M:O = 1:1 (and up to 1:1.25); with small to medium-sized cations only

Related to:

Periclase Group. Tenorite - Crednerite Series.

Crystal Data

Crystallography:

Monoclinic - Prismatic

Crystal Habit:

Lathlike crystals, flattened, elongated, to 2 mm; curved, scaly, dendritic; commonly pulverulent, earthy, massive.

Twinning:

On [011], contact plane, common, forming stellate groups; lamellar

Physical Properties

Cleavage:

[011] Poor/Indistinct in zones

Fracture:

Conchoidal to Uneven, Irregular

Tenacity:

Brittle

Hardness (Mohs):

3.5 - 4.0

Hardness (Vickers):

VHN₁₀₀=190 - 300 kg/mm²

Density:

6.45 - 6.50 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Black, Steel gray

Transparency:

Opaque; translucent on very thin edges

Luster:

Metallic

Refractive Index:

2.10 - 2.11  Biaxial ( ? )

Birefringence:

Anisotropic

Dispersion:

n/a

Pleochroism:

Weak; X = Light Brown, Z = Dark Brown

Anisotrohism:

Anisotropic. Strong: blue to gray
Bireflectance. Strong: light gray with golden hint

Occurances

Geological Setting:

In the oxidized zone of copper deposits, also as volcanic sublimate

Common Associations:

Azurite, Chrysocolla, Copper, Cuprite, Malachite, Fe–Mn oxides (hydrothermal); Alkali Chlorides, Copper Chlorides, Cotunnite (volcanic).

Type Locality:

Vesuvio (Vesuvius), Napoli, Campania, Italy

Year Discovered:

1841

View mineral photos:

Tenorite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Tenorite is a rare secondary copper oxide mineral that is rarely faceted. It is one of those gems for "black gem" collectors. It is usually opaque black with a metallic luster and fairly soft. Large, pure crystals for faceting are rare and typically found only as thin (2mm), scaley, lathlike crystals. Most locations produce Tenorite mixed with Azurite and Malachite. A recent find at the L'Etoile du Congo Mine (Star of the Congo Mine) and the Kalukuluku Mine, Lubumbashi (Elizabethville), Shaba, Congo (Zaïre) has produced some larger, pure crystals.

Tenorite is also found in the USA at several locations; Copper Harbor, Keweenaw County, Michigan; Darwin, Inyo County, California; an ore at Bisbee, Cochise County, Arizona. It is also found at several locations worldwide including Chuquicamata, Antofagasta, Chile; Tsumeb, Namibia; Ural Mountains, Russia.
 

  
Tenorite gems for sale: