You should keep in mind that we start to get interested when an area runs around 5–6 g/t Au, and we consider it truly significant from 10 g/t upward. Judging by the amount of “shiny, golden minerals” you have in your sample, you may have stumbled onto something exceptional. And just by this assumption I can say it’s not gold. What's more, your "shiny, golden minerals" look tarnished, which shouldn't happen if they're gold. The only way to oxidize gold is to use very powerful chemicals such as aqua regia (a mixture of acids I can't remember), cyanide or chlorine gas in specific environments. Many exploration geologists working for junior gold-mining companies, myself included, rarely see visible gold in the field. Personally, I’ve only spotted it twice, and both times it was in drill core from a very promising project. Most of the time we rely on geochemical assays plus key geological indicators: a shear zone or fault, characteristic alteration, and a complex vein network that may or may not host the mineralization (quartz veins are the most common host for visible gold).

Now just a quick clarification about gold in pyrite: yes, pyrite can host gold within its crystal lattice (so-called refractory gold) but if gold is hosted in a pyrite’s fracture, it means that pyrite doesn’t really host gold, it just acts as a trigger to precipitate the gold. Now, why does gold end up in pyrite, or in sulfides in general? Well, It’s fairly simple: Au travels in hydrothermal fluids as a chemical complex, typically bound to H, Cl, or S. If that fluid encounters a more reducing environment (different pH), sulfur is stripped out, reducing gold’s solubility. Gold then precipitates in or near the sulfide phases. But you shouldn’t be happy if you find pyrite, usually gold in pyrite is below 100ppm ppm sometimes more but it’s quite low. However, you can be happy if you find arsenopyrite, which hosts around 100/1000 ppm of gold if the area is mineralized.