The three main families of sulfide polymetallic ores are identified as volcanogenic massive sulphide family, the sedimentary exhalative family, and the Mississippi Valley type family. The classification of lead-zinc deposits in particular has been varied and resulted in a number of different organizations schemes.[1] The term "polymetallic ore" also includes nodules, principally Manganese nodules, that do not form as terrestrial deposits but as concretions on the ocean floor.[3][4]
Rocks containing polymetallic ores are often altered or formed by hydrothermal processes — chloritization, sericitization and silicification.[5][6] These deposits are often iron hydroxides containing cerussite PbCO3, anglesite PbSO4, smithsonite ZnCO3, calamine Zn4[Si2O7] [OH]2×H2O, malachite Cu2[CO3](OH)2, azurite Cu3[CO3]2(OH)2. Depending on the concentration of ore minerals, a distinction is made between solid or disseminated ores. Ore bodies of polymetallic ores are distinguished by a variety of sizes (having a length of several m to km), morphology (lenticular bedding deposits,[7]stockwork, veins,[8] nests, complex tube-like bodies) and occurrence conditions (gentle, steep, consonant, secant, etc.).[9]
^"Oʻzbekiston milliy ensiklopediyasi". National Encyclopedia of Uzbekistan (in Uzbek). Tashkent: National Encyclopedia of Uzbekistan State Scientific Publishing House. 2000–2005.