winchite

Winchite is a rare mineral belonging to the amphibole group. Its chemical formula is (CaNa)Mg3(Fe3+,Al)2Si6Al2O22(OH)2. It is characterized by the presence of both sodium and calcium in its structure, a feature that distinguishes it from many other amphiboles. Winchite typically forms in metamorphic rocks, often in association with other silicate minerals.

The mineral was first described in 1959 from a specimen found in the Wickenburg Mountains, Arizona, and was named in honor of geologist and mineralogist Steven Winch. It is known for its distinctive color, which can range from pale blue to blue-green, and sometimes exhibits a grayish hue. The crystal habit of winchite is commonly fibrous or acicular, meaning it forms needle-like crystals. It can also occur in massive or columnar aggregates.

Winchite is relatively soft, with a Mohs hardness of around 5 to 6, and has a vitreous to silky luster. It is typically opaque to translucent. Due to its rarity and the specific geological conditions required for its formation, winchite is not found in large quantities and is primarily of interest to mineral collectors and geologists studying metamorphic processes. Notable occurrences, in addition to the type locality in Arizona, include locations in Japan, Norway, and Canada.