Mineralogia do ouro - exemplos UDELAR – URUGUAY UFRGS – DEMIN - BRASIL 32 Examples of gold occurrence: 1 - exposed native gold (Au) and gold locked in pyrite (Py); 2 - electrum (Elc) with acanthite rims (gray); 3 - kustelite with acanthite inclusion and attachment (gray particle in black circle), it also has a pyrite insert with some fine- grained electrum inclusions (inside white circle); 4 - calaverite (Calv) associated with pyrite; 5 - unleached aurostibite (Aur) with a secondary rim (deep brown) and an altered aurostibite (inside white circle) from a cyanide leach residue; 6 - native gold (inside white circles) locked in FeOx from a flotation tail.