Help to ID some raw mineral specimens.

BornOnFire · Nov 4, 2011

I have some raw mineral specimens that I obtained in the neighborhood. I live in a big ol' Master Planned Community in close proximity to one of the biggest open pit copper mines in AZ. When the developer started building, he made a deal with the mine to use the discarded spoil from the mining operations. The result is some pretty good mineral specimens especially the milky quartz that these minerals are formed in. I have been looking at these rocks closely lately and noticed that some have the "dirty quartz" that is so appealing to the prospector. I took my rock hammer to some of these rocks and what I found inside is pretty interesting. Although I do see some sparkles of "Gold", I'm pretty sure that it's pyrite. The colors in these samples may mean other minerals are present but, I don't have the expertise. I thought that the community here would probably be interested to look and that you may teach me a thing or two about ID-ing minerals in the raw. Have a look.

UncleVinnys · Nov 5, 2011

We'd need a really close up, in-focus view to tell.

Green is probably copper.
Gold color could be gold flecks, pyrite, or citrine (if they are tiny crystals).

BioProfessor · Nov 5, 2011

Looks like schist and Gneiss to me.

Daryl

BornOnFire · Nov 5, 2011

This is the best my camera will do. Looks like a little peacock copper may in a few of these? Thanks for the help and replies!

High Plains Digger · Nov 7, 2011

BioProfessor: No schist, I will be gneiss to you. Really, no schist. That would be metamorphed mica, and I am not seeing either there. Lots of intrusive acton, typical in this kind of mine rock. There looks to be a bit of galena and sphalerite, lots of pyrite (iron sulfide) and chalcopyrite (copper sulfide) and some combinations of the two which leads to the thoughts of "peacock pyrite" as it tarnishes quite colorfully. Aparently a bit of "pure" copper here and there, probably some azurite (but that changes into something else with age. My age doesn't allow me to remember all the details). There are dozens of copper ores, mostly combinations of copper and other elements. The rock from those mines are chock full of all kinds of different things, and probably a bit of gold and silver here and there. Just depends on what the fluids had in them when the filled the cracks and crevices of rocks. Lots of quartz and many other minerals make up the body of the rock. It is interesting to see what was able to crystalize and what just solidified with all the "other soup". The small crystals indicate that it cooled somewhat rapidly. Fun rocks, and they make great yard rocks.