Zincite and Franklinite
Image: <a href="//commons.wikimedia.org/wiki/User:Islam90" title="User:Islam90">Islam90</a> (CC BY-SA 4.0)
Mineral NameZincite and Franklinite
Chemical FormulaZincite: ZnO; Franklinite: (Zn,Mn²⁺,Fe²⁺)(Fe³⁺,Mn³⁺)₂O₄
Mohs HardnessZincite: 4-4.5; Franklinite: 5.5-6
Streak ColorZincite: Orange-yellow; Franklinite: Reddish brown
CleavageZincite: Perfect on {1010}; Franklinite: None
FractureConchoidal to uneven
Specific GravityZincite: 5.66; Franklinite: 5.07-5.22
Colorsred, orange, yellow, black, brown
TransparencyZincite: Transparent to translucent; Franklinite: Opaque
Type LocalityFranklin and Sterling Hill, New Jersey, USA
Mineral GroupOxides (Zincite is a simple oxide, Franklinite is a spinel group oxide)
Usesore of zinc, ore of manganese, collector's mineral, synthetic forms of Zincite used in electronics
Associated MineralsWillemite, Calcite, Rhodonite, Andradite
Description
A microscopic image showing intergrown grains of light-colored Zincite and dark-colored Franklinite, characterized by irregular boundaries and numerous fractures.
Geological Context
These minerals are characteristic of the unique metamorphosed zinc-manganese ore deposits found at Franklin and Sterling Hill, New Jersey, formed under specific high-temperature, low-pressure conditions.
