Au-silicates from mesothermal gold deposits

Au-silicates occur at Maldon, Victoria, Australia as tight intergrowths with metallic gold. Their reflectivity is significantly higher than typical chlorite. Chemically these compounds are silicate-arsenates of Au³⁺. The gold content positively correlates with the arsenic content. Chlorites away from gold grains may contain detectable amounts of gold and an As₂O₃ content up to 1.2 wt.%. IFTR spectra of Au-As-silicates are generally similar to chlorite patterns, and indicate a content of organic compounds.