Zincite
Natural crystalline zincite, Franklin, New Jersey
General
Category	Oxide mineral
Chemical formula	(Zn,Mn)O
Strunz classification	04.AB.20
Dana classification	04.02.02.01
Identification
Color	Yellow-orange to deep red, rarely yellow, green, colorless
Crystal habit	Disseminated - Occurs in small, distinct particles dispersed in matrix.
Crystal system	Hexagonal Dihexagonal Pyramidal 6mm
Twinning	On {0001}
Cleavage	On {1010}, perfect; parting on {0001}
Fracture	Conchoidal
Tenacity	Brittle
Mohs scale hardness	4
Luster	Subadamantine to resinous
Streak	Yellowish orange
Diaphaneity	Translucent, transparent in thin fragments
Specific gravity	5.64 - 5.68
Optical properties	Uniaxial (+)
Refractive index	nω = 2.013 nε = 2.029
Birefringence	δ = 0.016
References	[1][2]

Zincite is the mineral form of zinc oxide (ZnO). In nature its crystal form is rare, with the exception of the Franklin and Sterling Hill Mines in New Jersey, an area also famed for its many fluorescent minerals. It has a hexagonal crystal structure and color that depends on impurities. The zincite found at Franklin Furnace is red-colored (mostly due to iron and manganese) and associated with willemite and franklinite.

Zincite crystals can be grown artificially, and synthetic zincite crystals are available as a by-product of zinc smelting. Synthetic crystals can be colorless or range in color from dark red, orange, yellow to light green.

Synthetic Zincite Crystals

Both natural and synthetic zincite crystals are significant for their early use as semiconductor crystal detectors in the early development of crystal radios before the advent of vacuum tubes. As an early radio detector it was used in a junction with another mineral, chalcopyrite, and the combination was known as the Perikon detector.

[edit] See also

• List of minerals

[edit] References

• Mineral galleries