Ludwigite is a magnesium

Magnesium

Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

-iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 borate mineral

Borate mineral

The borate minerals are minerals which contain a borate anion group. The borate units may be polymerised similar to the SiO4 unit of the silicate mineral class. This results in B2O5, B3O6, B2O4 anions as well as more complex structures which include hydroxide or halogen anions...

: Mg₂FeBO₅.

Ludwigite typically occurs in magnesian iron skarn

Skarn

Skarn is an old Swedish mining term originally used to describe a type of silicate gangue, or waste rock, associated with iron-ore bearing sulfide deposits apparently replacing Archean age limestones in Sweden's Persberg mining district. In modern usage the term "skarn" has been expanded to refer...

 and other high temperature contact metamorphic deposits. It occurs in association with magnetite

Magnetite

Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name is ferrous-ferric oxide. The formula for magnetite may also be written as FeO·Fe2O3, which is one part...

, forsterite

Forsterite

Forsterite is the magnesium rich end-member of the olivine solid solution series. Forsterite crystallizes in the orthorhombic system with cell parameters a 4.75 Å , b 10.20 Å and c 5.98 Å .Forsterite is associated with igneous and metamorphic rocks and has also been found in meteorites...

, clinohumite

Clinohumite

Clinohumite is an uncommon member of the humite group, a magnesium silicate according to the chemical formula 942. Most commonly found as tiny indistinct grains, large euhedral clinohumite crystals are sought by collectors and occasionally fashioned into bright, yellow-orange gemstones...

 and the borates vonsenite and szaibelyite. It forma a solid solution

Solid solution

A solid solution is a solid-state solution of one or more solutes in a solvent. Such a mixture is considered a solution rather than a compound when the crystal structure of the solvent remains unchanged by addition of the solutes, and when the mixture remains in a single homogeneous phase...

 series with the iron(II)-iron(III) borate mineral vonsenite.

It was first described in 1874 for an occurrence in Ocna de Fier, Banat Mountains

Banat Mountains

The Banat Mountains are a number of mountain ranges in Romania, considered part of the Western Romanian Carpathians group.The Banat Mountains consist of:* the Banat Mountains per se, which include:...

, Caras-Severin, Romania

Romania

Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

 and named for Ernst Ludwig (1842-1915), an Austria

Austria

Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

n chemist at the University of Vienna

University of Vienna

The University of Vienna is a public university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is the oldest university in the German-speaking world...

.