montebrasite

Montebrasite is a mineral belonging to the triphylite-montebrasite series. It is an anhydrous phosphate mineral with the chemical formula (Li,Na)Al(PO4)(OH,F). Montebrasite is the lithium-rich endmember of the series, while its close relative, ferri-montebrasite, is the iron-rich endmember. It is characterized by its pale color, often white, grayish, or pinkish, and typically occurs in prismatic or tabular crystals. The hardness of montebrasite is around 4.5 to 5 on the Mohs scale, and it has a specific gravity of approximately 3.1.

This mineral is commonly found in pegmatites, which are coarse-grained igneous rocks that form during the late stages of magma crystallization. Montebrasite often forms in association with other lithium-bearing minerals such as spodumene and lepidolite, as well as with minerals like quartz, feldspar, and mica. It can also be found in some metamorphic rocks.

Montebrasite was first described in 1878 from a locality in Montebras, Haute-Vienne, France, which gives the mineral its name. Significant occurrences of montebrasite have been reported in various locations worldwide, including Brazil, the United States (particularly in South Dakota and Maine), and Australia. Due to its lithium content, montebrasite has some economic interest as a potential source of lithium, which is a critical element in battery technology. However, its extraction and processing can be complex. It is also collected by mineral enthusiasts for its distinct crystal forms and geological associations.