blue basalt is the main bedrock with a brown conglomerate of quartz and other coloured rocks in sections running thru the basalt here and there. but I haven't seen any black rock about. I'll have to look a bit more at the rock formations around me and more research.Maybe the wood grubs are sharpening their teeth on gold now lol lol lol. classic!.The only rocks I've seen like that is in volcaic areas where the blackish larva melts onto everything it touches. It may well have come from an extinct volcano.
I'm from the Shoalhaven area., you get all kinds of mineralized rocks there with black around them, but I've never seen black with gold like that. Interesting!
going back this wend with the minelab xt and a 6 inch coiltek coil to cherry pick the area. I haven't used it much as I have been test panning and exploring the area for the past two years. I started a post up when I first joined the forum, about setting up the minelab xt. there is excellent setup tips from pa members on the post that have worked for me. I've only found a 0.01 gram nugget so far but it proves like other members on here said, it's still a very capable machine.I see that you have a minilab xt1700 how do like it, and do you still use it? I have on also that has been collecting dust in the shed for years. I brought it out the other week and gave it a clean, I plan on using it to check the rear tailings off my high banker.