It can be stalactitic, botryoidal to reniform massive with radiating coasrsely fibrous crystals. The best way to tell these two mineral apart is to use a streak plate. Limonite is a general term given to earthy mixtures of iron oxides, mostly goethite. Limonite's streak depends on the proportion of hematite to goethite present in the mixture. Despite all the iron in them, neither mineral is magnetic.
Magnetite gives a black streak.
When intermixed with hematite or goethite, it will darken their streak. Occassionally one will find black crystals, botryoidal masses or earthy material that is not magnetic, but does give a black streak. They are particularly common in the Cuyuna and Gogebic Ranges. Other iron oxides are known, but are rare. Goethite has three relatives that have the same chemical formula but different internal structures.