spindleite

Spindleite is a rare mineral composed primarily of copper, iron, and arsenic. Its chemical formula is often represented as Cu2FeAs2. It is a member of the sulfarsenide group of minerals. Spindleite typically occurs as small, prismatic crystals, which can sometimes resemble spindles, giving the mineral its name. These crystals are often found in aggregates. The color of spindleite is usually a dull gray to steel-gray. It is opaque and possesses a metallic luster. The hardness of spindleite on the Mohs scale is generally around 3.5 to 4. Spindleite is a relatively uncommon mineral, and significant deposits are not widely known. It is typically found in hydrothermal veins and in association with other copper and arsenic-bearing minerals. Its geological occurrence is often linked to sulfide ore deposits. The mineral was first described in the late 19th century, with its type locality often cited as a mine in the Tintic district of Utah, United States. Due to its rarity and relatively low economic value as a primary ore, spindleite is of more interest to mineral collectors and geologists than to industrial applications.