gems, beryl, emerald, Russia, Malysheva, Russian beryl, emerald mines, Ural Mountains

The Malyshevsk (Mariinsk) beryllium-emerald deposit, the most significant site within the Izumrudnye Kopi ore field on the eastern slope of the Middle Urals, has been reclassified in terms of genetic type and formation conditions based on integrated geological and mineralogical data. The deposit’s genesis is closely tied to granite-related hydrothermal activity within ultramafic host rocks, influenced by its tectonic setting at the deep-seated Susan fault zone between the Murzinsk-Aduisk microcontinent and the Rezhevsk volcanogenic depression. The ore field is associated with the eastern exocontact of the Aduisk granite pluton (278–201 Ma), emplaced at depths of 4–6 km. At this deep level, a unique paragenesis of rare-metal pegmatites (Nb, Ta, Be) and greisens (Be, Mo, Bi, F) formed under conditions of strong tectonism. Due to the ultramafic and basic nature of host rocks, the greisens appear as desilicified, phlogopite-rich micaceous rocks. The veins are dominated by plagioclase and contain beryl, emerald, chrysoberyl, phenakite, and bromellite. The ore field spans 1100 meters along strike, 110–150 meters in width, and over 500 meters down dip. Two ore body types are identified: beryl-plagioclase veins (0.25 wt % BeO) and emerald-bearing veinlet-metasomatic micaceous zones (0.089 wt % BeO), both linked to the same greisenization stage. Plagioclase-beryl veins are found in rigid rock blocks, while emerald-bearing metasomatic zones occur in pliable milonitic talc schists. Intense post-ore tectonics significantly altered the original ore body structure, fragmented beryl crystals, and led to the development of later hydrothermal beryllium assemblages. Despite extensive historical mining, the deposit remains a major source of emerald, juvenile chrysoberyl (alexandrite), phenakite, and fine mineral specimens, with beryl recovered as a byproduct.