Totally and THANK YOU VERY MUCH. In my humble opinion replies like yours should always be ranked first before the "tangents" appear. Again thanks.
Thanks, but that's the joy of posting on open forum - everybody is equal.
As a former flying instructor, I try to give good information whenever possible and believe strongly in good-quality teaching.
To that point, I can guide you towards a couple of excellent ED video-makers; they're excellent coaches and produce high-quality videos.
Look for CMDR Exegious and Down To Earth Astronomy; both are top-notch, entertaining and deliver their teaching in a point-by-point format.
Here are examples of both; each discussing precisely what you asked: Void Opal mining:
CMDR Exegious:
And Down To Earth Astronomy:
I strongly recommend both of these guys; they really help.
Cheers!