carpholite

Carpholite is a rare mineral that belongs to the amphibole group. Its chemical formula is MnAl2(BO3)(OH)3, indicating the presence of manganese, aluminum, boron, and hydroxyl groups. Carpholite is known for its distinctive pale to bright yellow or yellowish-brown color. It typically forms as slender, acicular (needle-like) crystals that can occur in radiating aggregates or as disseminated grains within host rocks. The hardness of carpholite on the Mohs scale is generally around 5, making it moderately hard. It has a vitreous to silky luster.

This mineral is found in metamorphic rocks, particularly those that have undergone low-grade metamorphism, such as schists and marbles. It often forms in association with other manganese-bearing minerals. Notable occurrences of carpholite have been reported in regions like Sweden, Japan, and parts of the United States. Due to its rarity and specific formation conditions, carpholite is not a widely exploited mineral and is primarily of interest to mineral collectors and geologists studying metamorphic petrology. Its presence can provide clues about the pressure and temperature conditions during the metamorphism of the surrounding rocks.