Ore genesis accumulation of hematite gravels called "pisolites" which form channel-iron deposits. These are preferred because they are cheap to mine. Lead-zinc deposits are generally accompanied by silver, hosted within the lead sulfide mineral galena or within the zinc sulfide mineral sphalerite. Lead and zinc deposits are formed by discharge of deep sedimentary brine onto the sea floor (termed "sedimentary exhalative" or SEDEX), or by replacement of limestone, in skarn deposits, some associated with submarine volcanoes (called volcanogenic massive sulfide ore deposits or VMS), or in the aureole of subvolcanic intrusions of granite. The vast majority of SEDEX lead and zinc deposits
Mineral industry of Armenia precious metal mines. Among these mines, about 400 mines, including 22 base metal, non-ferrous metal and precious metal mines are currently being exploited. Among the base metal and precious metal deposits, there are 7 copper-molybdenum mines, 3 copper mines, 13 gold and gold-polymetallic mines, 2 polymetalilc mines and 2 iron ore mines. In addition to those mines registered in the state inventory of mineral resources, there are an additional 115 deposits of various deposits that have been discovered. In 2017 mining industry output with grew by 14.2% to 172 billion AMD at current prices and run at 3.1% of Armenia's