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Zincite
Current inventory:  4 gems
 

Chemistry:  (Zn,Mn²⁺)O  [Zinc Manganese Oxide]

Discovered in 1845 ;   IMA status: Valid (pre-IMA; Grandfathered).
Zincite is named for its high zinc content. The name Zinc is from the German word zink.

Classification

Mineral Classification:

Oxides

Strunz 8th Ed. ID:

4/A.03-20

Nickel-Strunz 10th Ed. ID:

4.AB.20

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

Crystal Data

Crystallography:

Hexagonal - Dihexagonal Pyramidal

Crystal Habit:

Crystals rare, typically pyramidal, hemimorphic, to 2.5 cm, rarely curved; in broad cleavages, foliated, granular, compact, massive.

Twinning:

On [0001], with composition plane [0001].

Physical Properties

Cleavage:

[1010] Perfect; parting on [0001], commonly Distinct

Fracture:

Conchoidal

Tenacity:

Brittle

Hardness (Mohs):

4.0

Density:

5.64 - 5.68 (g/cm³)

Luminescence:

Usually None; rarely pale yellow fluorescence under LW UV

Radioactivity:

Not Radioactive

Optical Properties

Color:

Yellow, dark Yellow, Yellow-Orange, Orange, deep Red, rarely Green

Transparency:

Transparent, Translucent, Opaque

Luster:

Sub-adamantine to Resinous

Refractive Index:

2.013 - 2.029  Uniaxial ( + )

Birefringence:

0.0160

Dispersion:

0.127

Pleochroism:

None

Anisotrophism:

Weak; Color in reflected light: light rose brown

Occurances

Geological Setting:

A primary mineral in metamorphosed stratiform zinc orebodies (New Jersey, USA); a secondary mineral altered from other zinc minerals in oxidized zinc-rich ore deposits; a product of volcanism.

Type Locality:

Franklin Mine, Franklin, Franklin Mining District, Sussex Co., New Jersey, USA; Sterling Mine, Sterling Hill, Ogdensburg, Franklin Mining District, Sussex Co., New Jersey, USA

Year Discovered:

1845

View mineral photos:

Zincite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Zincite is an amazingly beautiful and very rare gem with intense colors of red, orange, yellow and green. Its refractive index is close to a diamond's (2.417) and therefore has lots of fire. Gem quality Zincite crystals have been found in only a few locations in the world. The most notable is the Franklin Mining District, New Jersey. Gems from there are extremely rare and are usually very dark red, almost opaque. Another source of Zincite gems is a smelter at a Zinc mine at Breslau, Silesia, Poland. Zincite crystals were formed accidentally as the result of a chimney fire in a smelter at the Zinc mine. These crystals are not considered synthetic since they weren't grown in a laboratory environment but are not a natural crystal. These crystals have been used to cut some of the brightest and most highly refractive gems with superb colors ranging from deep red to deep green including bright orange, lemon yellow and bright green.
 

  
Zincite gems for sale: