This list of ores classified as natural and rare gold minerals are refractory to process. All these are sulphides refractory gold bearing minerals and will have a poor response behaviour to usual cyanidation extraction methods, and for the little guy, best used for exhibit or sold to rock collectors on eBay.
Very Rare Crystal. Yellow white, opaque; Perfect Cleavage. Mohs 2.5-3.5; SG 7.5-8 Dana number: 442
Rare telluride, and it contains ~ 50 wt% Au
Naturally occurring alloy of gold and rhodium with an SG of 15.5 – 16.8
Natural alloy of gold and iridium containing 62% gold, 30% iridium, 4% platinum, and 2% silver.
Hardness: 2.5-3 and Density: 12.5-15.5
Natural gold alloy containing 5-10 wt % Pd
Opaque, Pale pink in reflected light, Metallic luster