Goethite
Real mineral · common · Fe+++O(OH)
Iron hydroxide, the brown of rust and of ochre, and the main constituent of the field mixture called limonite. Its botryoidal crusts cap oxidised iron and copper deposits the world over.
Identity
- Formula
- Fe+++O(OH)
- Chemical class
- oxide
- Also known as
- Needle ironstone
Crystallography
- Crystal system
- orthorhombic
- Habits
- botryoidal, acicular, massive, earthy
- Fracture
- hackly
Physical properties
- Mohs hardness
- 5
- Density
- 3.8 g/cm³
- Luster
- adamantine, silky
- Colors
- brown, reddish brown, yellowish brown, brownish yellow, ocher yellow
- Streak
- yellowish brown
- Transparency
- translucent, opaque
Geology
- Origins
- sedimentary, hydrothermal
- Host rocks
- gossan, bog iron
- Associated minerals
- Hematite, Pyrite, Quartz, Malachite
- Geography
- worldwide
Classification
- Rarity
- common
- Gem quality
- No
Browse the Crystal Encyclopedia — MGS Toolbox