baddeleyite

Baddeleyite is a rare mineral consisting of zirconium oxide, with the chemical formula ZrO2. It is the monoclinic polymorph of zirconium dioxide that is stable at ambient Earth-surface conditions, distinguished from the metal’s high-temperature phases.

Occurrence and formation

Baddeleyite occurs mainly in carbonatites and alkaline igneous complexes, where it can form as euhedral to subhedral crystals in the groundmass or as inclusions in other minerals. It is also reported in some metamorphic rocks and, less commonly, in impact melt rocks associated with meteorite impacts. Its associations often include minerals such as zircon, apatite, titanite, and fluorite.

Structure and properties

As a monoclinic oxide mineral, baddeleyite shares the crystal structure of ZrO2 found in natural, unstabilized zirconia. It typically appears colorless to gray and has a vitreous to resinous luster. The mineral is relatively dense for oxides and tends to form compact, euhedral crystals. It is resistant to weathering and can persist in a variety of geological environments.

Geochronology and industrial relevance

Baddeleyite is of particular interest to geochronologists because it can incorporate uranium and lead into its crystal lattice, enabling U-Pb radiometric dating of rocks. This makes it valuable for dating carbonatites, kimberlites, and other ultramafic or alkaline suites. Economically, it is a minor zirconium ore in certain deposits, though it is not the primary source of zirconium compared with zircon crystals.

See also

List of minerals; Zirconium minerals; U-Pb dating.