Maldonite in gold and rare-metal ore occurrences of the Myakit-Hurchanskiy ore-placer cluster (North-East of Russia)
Grain mineral maldonite identified by dissolving in hydrofluoric and nitric acids piece of ore material samples from quartz veins of Kunkuyskoe and Front ore occurrences in the south-east flank of the Yana-Kolyma gold belt. In addition to micro-maldonite in native gold are three varieties of his discharge, as follows: 1) very small independent grains; 2) maldonite allocation with fragmented shell of high-grade gold nuggets; 3) intergrown pieces of maldonite grains with a very high-grade native gold eloquently-looped (or eloquently spongy) texture with bismuth oxide. In the Front ore occurrence in the early stages of mineralization formation, maldonite grains approximately accounted for 25 % of the total number of maldonite and native gold selections, in the Kunkuyskoe ore occurrence - about 45 %. In future as a result of hypogene decomposition occurred a replacement of some part of maldonite by very high-grade native gold of eloquently-looped texture associated with bismuth oxides. In the Front ore occurrence decomposition affected 90 % of maldonite discharges; this process reaches deep stage in 80 % of maldonite and 53 % were fully decomposed on native gold and bismuth oxides. In the Kunkuyskoe ore occurrence about 30 % of the maldonite grains were decomposed, half of them - to full. Maldonite decomposition happened with gold solutions.