Image: <bdi><a href="https://www.wikidata.org/wiki/Q56247090" class="extiw" title="d:Q56247090"><span title="mineral collector and dealer">Robert M. Lavinsky</span></a></bdi> (CC BY-SA 3.0)
orthorhombicuncommonOxides
Goethite
FeO(OH)
This specimen features radiating, acicular (needle-like) crystals of goethite, displaying a dark brown to black color with a velvety or silky luster.
Goethite Physical Properties
Mohs Hardness
5Crystal System
orthorhombicLuster
adamantineStreak Color
yellowish-brownCleavage
perfect on {010}, rarely observedFracture
unevenSpecific Gravity
3.3Colors
black, brownish-black, reddish-brown, yellowish-brownTransparency
opaqueType Locality
Crystal Peak area, Teller County, Colorado, USAMineral Group
OxidesUses
iron ore, pigment, collectorAssociated Minerals
hematite, limonite, quartz, calciteRarity
uncommonGeological Context
Goethite is a widespread secondary mineral formed by the weathering of iron-bearing minerals, commonly found in the oxidized zones of ore deposits, bog iron ores, and as a major component of limonite. It forms in low-temperature, near-surface environments.
