Franklinite
Mineral ZnFe2O4
About it
Black, rounded octahedrons that a magnet pulls weakly, with a reddish-brown streak. Almost unique to Franklin and Sterling Hill, New Jersey, where it sits with red zincite and green willemite.
- Type
- Mineral
- Group
- Oxide, spinel group
- Formula
- ZnFe2O4
- Hardness (Mohs)
- 5.5–6.5
- Specific gravity
- 5.07–5.22
- Streak
- reddish brown to dark brown
- Lustre
- metallic, submetallic
- Crystal system
- Isometric (cubic)
- Colours
- black
- Transparency
- opaque
- Cleavage and fracture
- none; octahedral parting, uneven to subconchoidal fracture
- Magnetic
- Weakly
Typical values: real specimens vary. For more, see mindat.org.