Trolleite is an aluminum phosphate hydroxide mineral, typically occurring in shades of blue, violet, or greenish-blue due to trace amounts of iron. Its key characteristics include vitreous to resinous luster, a hardness of 5.5-6 on the Mohs scale, and a triclinic crystal system. A common occurrence is as massive or fibrous aggregates, often intergrown with other phosphate minerals.
Understanding the distinct attributes of this mineral is essential for geologists, mineralogists, and collectors. Its presence can indicate specific geological formations and processes. Historically, trolleite has been a subject of study for its crystallography and formation conditions. While not a widely used industrial mineral, its unique optical properties make it an attractive specimen for collectors.