Massive Goethite and Limonite can be indistinguishable. Limonite forms mostly in or near oxidized iron and other metal ore deposits, and as sedimentary beds. Limonite has been known to pseudomorph other minerals such as pyrite , meaning it replaces a crystal of pyrite with limonite but keeps the shape of the pyrite crystal. Color is yellow, orange, reddish brown, brownish black. Luster is earthy to dull.
Transparency is opaque.
Crystal System is undefined. Crystal Habits include massive, layered, botryoidal and stalactitic. Cleavage is absent. Fracture is crumbly or earthy. Streak is brownish yellow to yellow.