FMF - Friends of Minerals Forum, discussion and message board

[Ken]

A lot of the minerals from where this was found appear to have been in an environment that has altered/modified them. Came across a lot of what looks like quartz but the composition seem a bit more complicated than common quartz. With all of these impurities, would this stone still be classified as quartz? The first scan shows the composition of the stone and the second shows the composition of that copper colored material.

[Pete Modreski]

This appears to be a quartz-mica schist; the presence of the mica (all the sparkling flakes, of course) would account for the other elements (K, Ca, Mg, Fe, Al) that show up in the X-ray spectrum.

There is a complete gradation possible, between pure quartzite (metamorphic rock, metamorphosed quartz sandstone) containing nothing but quartz, and mica schists that are a mixture of mica, quartz, and other minerals. Your rock appears to be mostly quartz, with the muscovite mica concentrated in certain thin layers.

Pete

[Matt_Zukowski]

How are you doing or getting these scans done?

[Ken]

[Pete Richards]

Ken,

A lot of this thread involves themes of rocks and minerals changing, and you met a geologist who spoke of very high temperatures and pressures. All of this points to metamorphism and the rocks that it produces, yet almost no one seems to be writing in such terms. I suggest you get ahold of a basic geology text and read about metamorphism. You might go farther and read about various kinds and degrees of metamorphism, the minerals that indicate them, and the kinds of temperatures and pressures that are involved. I think this would illuminate many of your questions.

Incidentally, that geologist fellow's mention of shock metamorphosis is probably off base. It is an uncommon process and it would be very hard to recognize just looking at a hand sample of a rock.

The issue with your new (second) scan with the iron, chromium, and titanium is the same as earlier - we don't know what part of the image was actually analyzed. The title says copper quartz metallic, which I guess probably means a copper-colored metallic mineral associated with quartz. The analysis is definitely not of mica, but it could be of a little spot in the picture, with all the rest being mica.

[renewillard39]

Great, thank you.

[Ken]

[Matt_Zukowski]

The reason I asked is because you seem like a newbie (forgive me if I am wrong), and you are the first newbie I have heard about who is paying for/doing such analyses.

Are you just picking up rocks that you think are cool and sending them off for analyses, or do you have some more systematic reason for getting these analyses done?

No matter, I salute your inquisitiveness.

[Ken]

Hi Matt- I guess you might say that my curiosity got the best of me. I stumbled onto some minerals that were being washed out of a mountain that were setting off my metal detector, a lot of these minerals were very magnetic and I wanted to figure out what was going on. I bought a hardness test set, specific gravity test set and even a refractive index meter. I was told the best way to figure out what a mineral was is to figure out what the chemical composition is, but every time I'd get a scan done, I'd be told that can't be right. I've come across a lot of things that can't be easily explained. I'm just searching for answers, and yes I'm very much a newbie at this.

[Matt_Zukowski]

Interesting. Have we suggested that you find a local rockshop/rock club/college geology department that you can take your unknowns to and ask around? I think that would be the best way for you to make progress.

There are also many books and internet resources on basic geology and mineralogy that could give you some context.

Anyways, I again salute your inquisitiveness.

[Ken]