Limonite

     Limonite is a generic term currently used for undifferentiated hydrated iron oxides - often hydrated Goethite, with no visible crystals, and a yellow-brown streak. Limonite is not an IMA approved the mineral name. Although it is most commonly the mineral species Goethite, it can also consist of varying proportions of Maghemite, Hematite, Lepidocrocite, Hisingerite, Pitticite, and Jarosite Group species, etc.  The Characteristics of stone limonite is relatively dense with a gravity this is actually specific from 2.7 to 4.3. It varies in colour from a lemony this is actually bright to a drab greyish brown. The streak of limonite on an unglazed porcelain plate is actually brownish, a character which distinguishes it from hematite with a red streak, or from magnetite with a streak this is actually black. The hardness is variable, but generally, once you glance at the 4 - 5.5 range.

     Although originally thought as a mineral this is actually single limonite happens to be regarded as a mixture of related hydrated iron oxide minerals, one of those goethite, akaganeite, lepidocrocite, and jarosite. Individual minerals in limonite may form crystals, but limonite will likely not, although specimens may show a fibrous or structure this is actually microcrystalline and limonite often occurs in concretionary forms or simply in compact and earthy masses; sometimes mammillary, botryoidal, reniform or stalactitic. Because of its nature, this is actually amorphous occurrence in hydrated areas limonite often presents as a clay or mudstone. However, you'll find limonite pseudomorphs after other minerals such as pyrite. Which means that chemical weathering transforms the crystals of pyrite into limonite by hydrating the molecules, however, the external style of the crystal this is really pyrite. Limonite pseudomorphs also have formed off their iron oxides, hematite, and magnetite; through the carbonate siderite and from iron silicates that could be rich as almandine garnet.  While Limonite is amorphous, a number of minerals are noted for decomposing to it without losing their crystal shape - particularly Pyrite crystals. Any "crystals" of "Limonite" are actually pseudomorphs of other minerals which have decomposed in this fashion. Limonite is typically massive and may be very soft.  Limonite is a very common material in the oxidized zones of iron-bearing deposits and can be found at many locations worldwide.