Input needed...

[dtinhb]

Hey All,

I posted these pics the other day in the Meteorite forum, but didn't get a response. I have poured through the internet trying to understand what I've got and am leaning towards meteorites, but I am curious to get some feedback... In case I am missing something. There are two separate rocks and the first 6 pics are of one and the last 6 are of the other....


**In some of the photos you can see the gold specks really well, but the other metal was a little more difficult to capture especially with the first rock.

 

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[IAMZIM]

Keep in mind I am not an expert geologist, but, the pics are kind of hard to tell. The first pic looks very much like a sulfide type mineral to me, like bornite, the "gold" flecks look like pyrite to me, also a sulfide. "Pyrite forms due to a chemical process initially caused by the decomposition of organic matter in bacterial sulfate reduction. The bacterial sulfate reduction produces an inorganic anion known as bisulfide, which reacts with iron minerals to form iron sulfides, the most common of which is pyrite." I am quoting this from a book. As far as I know, sulfides are made from processes that happen on earth, all a chemical process which I don't think can happen in space, because I believe there would need to be oxygen as well as other gases, and water needs to be present I believe, for pyrite or any sulfide to be formed. Things like O2 and H2O are really rare in space, So, I guess I would say, that I don't think it is a meteorite. The characteristics don't match IMHO. If, it was on earth long enough to form sulfides, it would probably have more of a rusted patina as well due to weathering. The black I am seeing looks like black stone here where I am at, which is manganese as well as silver ore. You might look into the geology of your area, it looks just like the copper/silver/gold ore from my area. Like I said, I'm no expert, and I may be off on this. Hopefully someone with more experience than me can help you. FYI: if it does not turn out to be a meteorite, and I'm right about it, it would be a good candidate for crushing and panning, you may get some gold out of it.....

 

[dtinhb]

Yeah, I know it can be tough with the pics and all, but the "gold" in there is most definitely metal not crystal or flakey. Looks like little gold balls or in some cases sheered gold from the cut. The green in there is most definitely some kind of silicate. While both affect a strong magnet hanging from a string, they barely affect it. I looked at bornite and it's not even close. Which I am not faulting you for it, it is tough to get the pictures to represent the reality. I'll keep positive, but if someone can show me I am off on this one, I would most gladly step back into reality. Thanks for your input... It is appreciated!

 

[IAMZIM]

I hope I am wrong!

 

[dtinhb]

LOL... Me and you both.

 

[Eu_citzen]

Do a hardness test (will a knife scratch it?) and a streak test. (rubb against unglazed porcelain - what color do you get?)
Not likely to be a meteorite IMHO.

 

[dtinhb]

A knife won't scratch it and the streak is dark brown...

 

[Eu_citzen]

Interesting! I'd need to see a better, less blurry picture of the "fresh surface". (as in the last pic)

If I were you, I'd be looking for where that came from. If I find it, have it assayed.

 

[dtinhb]

Thanks EU, I appreciate it... I cut a slice off of each and took a few more photos.

I would look where I got it from, but these are part of the haul I brought home on my last road trip to St. Louis, so it could be anywhere from here (SoCal) to Missouri. I have a few spots that I spent more time at, so when I get the chance for another road trip, I will check those out.

Have you ever checked out meteorlabs.com... They do a cheap preliminary verification of up to 3 samples for $20. They don't classify it, but offer a "yes/no" determination. I figured I might just ship off a few of these slices and see what they say.
Slice from Rock #1:
Polished side


Fresh Side


This is the best closeup I could get


Slice from Rock#2
Polished side


Unpolished side


And yes, I suck cutting rocks with my cheap saw... LOL

 

[dtinhb]

Here is a video too:

 

[Moesia]

Serpentinized peridotite.

 

[dtinhb]

I am not sure the intent behind the reply because, unless I am missing something here (and it is quite possible), "Serpentinized peridotite" looks nothing like ANY of those pictures. For instance, I am not sure how you look at the above pictures and think of these rocks:


As opposed to these:



Again, maybe you have something I am missing here, but it seems like you are going out of your way to discourage me from testing them. It would be different if you didn't state it as a matter-of-fact. But whatever works for you... Good luck with that. I may have a rock and not a meteorite... But at least my rock has some personality.

 

[Moesia]

I did not know that "serpentinized peridotite" is an insult. It is an opinion. You're pictures do not have enough clarity to say anything definitely. They are probably more mafic than ultramafic considering what appears to be pyrite in them. As for the rocks in you're last post, they are not a typical representation of serpentinized peridotite. The appearance of serpentinized peridotite varies widely depending on the amount of serpentinization and subsequent hydrothermal alteration. My assessment of you're specimen is based purely on general appearance of the rock and not on it's mineralogy, as the picture clarity is simply not there. Also next time try to brake the rock with a hammer, do not try to cut it with a saw. It leaves white cut marks that obscure the fresh surface.
If you wont hear an opinion don't post it asking what it is. Have it assayed by all means if you have the resources.

 

[Eu_citzen]

Well, we do know a knife won't scratch it. So serpentine isn't likely.


When we speak of a fresh surface, we usually mean you need to chip of a piece with a hammer. So we can see luster, cleavage etc.
I'm thinking silica-related. Rhyolite? Or a metasomatically altered something?

 

[dtinhb]

I did not know that "serpentinized peridotite" is an insult. It is an opinion. You're pictures do not have enough clarity to say anything definitely. They are probably more mafic than ultramafic considering what appears to be pyrite in them. As for the rocks in you're last post, they are not a typical representation of serpentinized peridotite. The appearance of serpentinized peridotite varies widely depending on the amount of serpentinization and subsequent hydrothermal alteration. My assessment of you're specimen is based purely on general appearance of the rock and not on it's mineralogy, as the picture clarity is simply not there. Also next time try to brake the rock with a hammer, do not try to cut it with a saw. It leaves white cut marks that obscure the fresh surface.
If you wont hear an opinion don't post it asking what it is. Have it assayed by all means if you have the resources.

It's all good... I didn't take it as an insult, but as the saying goes, "throwing shade". My point was that I was asking for input (as was graciously provided by EU) and your comment was without context and referenced something that I couldn't find one pic of that even halfway resembled the pics I included above.

However, your last post, was much more helpful in understanding where you are coming from. My whole point is that what if it was a meteorite, which you could not definitively rule out based on pics, and you input discouraged them from ever taking more of a definitive approach. Don't get me wrong, I don't think there is anything wrong with giving people a dose of reality based on your experience, but I think if you are going to take a whiz on their "sunshine" then you could at least leave a window of hope for them (when you can't definitively say otherwise)...

That's it... But I do appreciate your response within the context of your second post...

 

[dtinhb]

Well, we do know a knife won't scratch it. So serpentine isn't likely.


When we speak of a fresh surface, we usually mean you need to chip of a piece with a hammer. So we can see luster, cleavage etc.
I'm thinking silica-related. Rhyolite? Or a metasomatically altered something?

Yeah, I get that now... I looked at Rhyolite and can agree that it can't be ruled out... But for $20, to get a definitive test done, its worth it. I will let you know what happens.

Thanks For Your Insight and All that you help around here... It's appreciated! _DT