mineral

Goethite–limonite ironstone specimen

Goethite (FeO(OH)) with limonite (hydrated iron oxides), possibly quartz and manganese oxides

AI-generated identification · may be incorrect

Hardness about 5–5.5 (goethite), earthy to submetallic luster, brown-black to yellow-brown colors, massive/botryoidal texture, and high specific gravity around 3.3–4.3. The pale gray coating may be weathered iron oxide or associated quartz; exact identification requires testing.

Identified August 29, 2026More mineral →

Explore Goethite–limonite ironstone specimen in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Forms by oxidation and weathering of iron-bearing minerals, commonly in hydrothermal veins, gossans, bog deposits, and ore zones; ages range from recent weathering to ancient deposits. Common worldwide, including Australia, Brazil, the United States, and Europe.

Uses & applications

Primarily an iron ore and pigment source; attractive botryoidal specimens are collected, though it is not typically used as a gemstone or construction stone.

Geological facts

Goethite commonly produces yellow-brown streaks and may occur with hematite, limonite, quartz, and manganese oxides. Its rusty appearance reflects oxidation rather than a single pure mineral phase.

Field identification & locations

Look for very high density, rusty brown or yellow-brown streak, earthy/botryoidal surfaces, and lack of strong cleavage; a streak test and hardness test help distinguish it from metallic sulfides. The pictured specimen is most consistent with iron-oxide mineralization, but visual identification is not definitive.