Knebelite is a term primarily used in the field of mineralogy to describe a rare and distinctive mineral species belonging to the pyrochlore supergroup. It is typically classified as an oxide mineral and is composed of the chemical elements sodium, calcium, tantalum, niobium, oxygen, and fluorine. The mineral is named after Harald Knebel, a German mineralogist who made significant contributions to the study of mineralogy.
Knebelite typically forms as small, octahedral crystals or as massive aggregates. It has a characteristic reddish-brown to black coloration, with a submetallic to adamantine luster when polished. The mineral is often found associated with other minerals such as calcite, quartz, and manganotantalite in various geological environments.
In terms of its physical properties, knebelite has a relatively high density and hardness, which makes it resistant to scratching. It also exhibits a subconchoidal fracture, indicating that it breaks with smooth, curved surfaces. Its crystal structure is cubic, and it belongs to the Fd3m space group.
The mineral is primarily recognized for its occurrence in rare metal-rich pegmatites, which are geological formations known for hosting deposits of economically significant minerals. Due to its scarcity, limited information is available regarding its potential applications or uses. However, in the field of mineralogy, knebelite serves as an important component for scientific study and exploration of rare mineral occurrences.
