Mahutites

Mahutites are a rare phosphate mineral species related to the apatite group. They were first described from the Mahuta Basin, a geologically active locality, and are named for the region where the initial specimens were found. The species is recognized for its distinctive combination of composition, crystal habit, and occurrence in hydrothermal environments.

Physically, mahutites crystallize in the monoclinic system and are typically found as prismatic to tabular crystals that reach up to a few millimeters in size. They exhibit a vitreous to glassy luster and a pale yellow to olive color, with a white to pale streak. The mineral is usually transparent to translucent and has a Mohs hardness around 5.5. Reported specific gravity values generally fall in the 3.2 to 3.4 range, reflecting its phosphate-rich composition. Optically, mahutites are biaxial and show moderate refractivity.

Composition and structure are best described as calcium- and sodium-rich phosphates with substitutions by magnesium, iron, and fluorine or hydroxide. The general formula is approximated as a Ca,Na-rich (PO4) compound with variable amounts of Mg and Fe substituting for Ca, and with F or OH occupying minor anion sites. This solid-solution behavior places mahutite within the broader apatite-family framework, though it remains a distinct and comparatively rare member.

Distribution and formation occur in hydrothermal veins associated with granitic and felsic rocks. Mahutites are typically linked with quartz, calcite, and other phosphate minerals, forming during late-stage mineralization under moderate temperatures and controlled phosphate activity. While not known as an ore mineral, mahutites are of interest to researchers for insights into phosphate mineral chemistry and hydrothermal processes, as well as to mineral collectors seeking unique examples from constrained locales.