Properties of Goethite

Goethite is a mineral that is composed of iron(III) oxide-hydroxide, with the chemical formula FeO(OH). It is one of the most common iron minerals and belongs to the diaspore group. Goethite can be found in various geological settings, including sedimentary, metamorphic, and hydrothermal environments.

Image of goethite mineral
Credit: Marie-Lan Taÿ Pamart, CC BY 4.0, via Wikimedia Commons

The following table provides a comprehensive list of goethite properties in both SI and US customary/Imperial units at normal temperature and pressure (NTP).

Note: click on the icon to switch between Metric and Imperial units.

Table of Goethite Properties
Physical Properties
Metric
Chemical Formulaα-FeO(OH)
Molar Mass88.85 g/mol
Crystal SystemOrthorhombic
Mohs Hardness5 - 5.5
Density4270 kg/m3
ColorBrown, black, reddish brown, or yellowish brown
DiaphaneityTranslucent to opaque
LusterSubadamantine, silky
Cleavage(010) perfect
FractureUneven, hackly
StreakYellowish brown

Note: unless stated otherwise, all values are taken at room temperature (approximately 20°C or 68°F) and 1 atm pressure. (1 atm = 101,325 Pa)

Related Pages
References: 1) Cardarelli, François. Materials Handbook: A Concise Desktop Reference. Switzerland: Springer International Publishing, 2018. 2) CRC Handbook of Chemistry and Physics, 97th Edition. United Kingdom: CRC Press, 2016-2017.