Nadorite
Nadorite is a rare halide mineral with the chemical formula PbSbO2Cl. It is a lead antimony oxide chloride.
Occurrence and Formation:
Nadorite typically occurs as a secondary mineral in oxidized portions of lead and antimony ore deposits. It is often associated with other secondary minerals such as bindheimite, cerussite, and valentinite. The mineral forms through the alteration of primary sulfide minerals in the presence of chlorine-bearing solutions.
Physical Properties:
Nadorite commonly presents as prismatic crystals, often elongated or acicular (needle-like). It can also occur as massive or granular aggregates. The color ranges from yellowish-brown to reddish-brown to dark brown or nearly black. It has a vitreous to adamantine luster. Nadorite is brittle and has a conchoidal fracture. Its hardness on the Mohs scale is typically between 3.5 and 4. The streak is pale yellow to white. Nadorite is translucent to opaque.
Chemical Properties:
Nadorite is relatively insoluble in water but can dissolve in strong acids. It is characterized by the presence of lead (Pb), antimony (Sb), oxygen (O), and chlorine (Cl) in its chemical composition.
Identification:
Nadorite can be identified by its characteristic crystal habit, color, luster, and association with other secondary minerals in lead and antimony deposits. X-ray diffraction analysis is often used to confirm its identification.
Uses:
Due to its rarity, nadorite does not have significant commercial applications. It is primarily of interest to mineral collectors and researchers studying the geochemistry of ore deposits.
Etymology and History:
Nadorite was first described in 1870 by A. Lacroix. It is named after Djebel Nador, near Constantine, Algeria, where it was first discovered.