Humboldtine
Mineral Fe2+C2O4·2H2O
About it
Soft yellow crusts and tiny crystals of iron oxalate formed in brown coal and lignite. Named for explorer and naturalist Alexander von Humboldt.
- Type
- Mineral
- Group
- Organic compound, oxalate
- Formula
- Fe2+C2O4·2H2O
- Hardness (Mohs)
- 1.5–2
- Specific gravity
- 2.2–2.3
- Streak
- pale yellow
- Lustre
- resinous, dull, earthy
- Crystal system
- Monoclinic
- Colours
- yellow, amber yellow, yellowish brown
- Transparency
- translucent, opaque
- Cleavage and fracture
- perfect in one direction
Typical values: real specimens vary. For more, see mindat.org.