Got A Rock you Want Identified? Post it here! gimme a good picture or 3 or 4!

The first is with flash on and is a decent rep but the transparency is milky closer to the top and bottom and is clear in the middle. Is this an algae or natural colorization? I tried the bleach suggestion to remove possible algae...no change. It doesn't appear vivid enough to be emerald and darker than most peridot I have seen. It was originally found on a white quarts chuck that I found hiking in the woods. I assume another layer of quartz was on the other half due to the same marks after this broke off the main chunk. It is brittle, this piece here just broke in half when it fell on the floor...what is it?View attachment 1421046View attachment 1421047View attachment 1421048

The images aren't quite as focused as I'd like them. But did you consider it's just quartz?
Green inclusions can occur in quartz, giving it a green colour, especially so if the quartz during formation chemically acted on the rock surrounding it.

I'd say, it's natural, though.
 

Hey guys, there's this sedimentary rock that I'm having troubles identifying. Is it ferruginous oolitic limestone? Are those fossiles in there?
Thanks for your help,
Keep rocking !

IMG_20170131_140907.jpg
 

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Hi everyone - my first post here - found the thread while trying to identify some rocks. I'm very grateful to Dusted for starting this thread! I've broken my back and neck in three different locations and pretty much torn every joint - again as a result of a drunk driver. I think I was luckier than you, Dusted, and less surgeries, it sounds - but I can understand!

Thanks to EU_Citizen for chipping in here also, while Dusted has been been out of circulation. Hopefully one of you can give me some guidance on the five samples I will post below - they came from 3 rivers that source near a location in some mountains that I'm interested in. Many of the rocks show a lot of similarity - I'm hopeful that means that the area of interest covers quite a large area

For ease, I'll make a separate post for each of the rocks, with a few pics each?

This first one has shown in rocks from all three rivers, some of them quite large chunks. One of the rivers, the chunks were quite jagged, meaning close to the source?

Lots of metal showing in the central quartz area, surrounded by the iron stain, however, small nuggets of something else in other areas also. I'm guessing some silver in there, but curious as to chances of gold

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This next one was found higher up in the river, but seemed to get pulverised easily and couldn't find samples lower down. Calcite with sulphides/metals?

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This next one also seems to show some metallic inclusions, and some sulfides?

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The last one doesnt seem of interest in terms of metals - but I'm curious as to what it is anyway lol

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Hey guys, there's this sedimentary rock that I'm having troubles identifying. Is it ferruginous oolitic limestone? Are those fossiles in there?
Thanks for your help,
Keep rocking !

View attachment 1422235

A easy test at home for limestone: Put a drop of vinegar on it. Limestone is made up mostly of calcite will make it bubble and fizzle.
Rinse with water after the test.

And yes, I'd guess that there are several small fossils in there. I don't think I'd call it oolitic, however.
 

Hi everyone - my first post here - found the thread while trying to identify some rocks. I'm very grateful to Dusted for starting this thread! I've broken my back and neck in three different locations and pretty much torn every joint - again as a result of a drunk driver. I think I was luckier than you, Dusted, and less surgeries, it sounds - but I can understand!

Thanks to EU_Citizen for chipping in here also, while Dusted has been been out of circulation. Hopefully one of you can give me some guidance on the five samples I will post below - they came from 3 rivers that triangulate a location in some mountains that I'm interested in. Location is in the Caribbean, near a subduction zone. many of the rocks show a lot of similarity - I'm hopeful that means that the area of interest covers quite a large area

For ease, I'll make a separate post for each of the rocks, with a few pics each?

This first one has shown in rocks from all three rivers, some of them quite large chunks. One of the rivers, the chunks were quite jagged, meaning close to the source?

Lots of metal showing in the central quartz area, surrounded by the iron stain, however, small nuggets of something else in other areas also. I'm guessing some silver in there, but curious as to chances of gold

View attachment 1422299View attachment 1422300View attachment 1422301View attachment 1422302


An interesting rock. I'd try find some of it exposed in bedrock to hazard a better guess.
A pic of the exposure might even help to indicate what caused the alteration. My hunch: Fault- or shear zone.

It does appear to have been altered by hydrothermal fluids - a good thing - and to hazard a guess; might (originally) be a granitoid.
From a hunch, I'd say a half-way decent chance of interesting metals. I'd crush and pan some, as a indication if assaying might be worthwhile.

I have similar rocks from Sweden waiting for assay now. Mine came from a shear zone.
Either way, that's what I'd do.
 

This next one was found higher up in the river, but seemed to get pulverised easily and couldn't find samples lower down. Calcite with sulphides/metals?

View attachment 1422303View attachment 1422304View attachment 1422305View attachment 1422306View attachment 1422307

Calcite will react with vinegar, bubbling and fizzling. Do the test. But the looks do have a chalcedony-ish look to it. Most times however chalcedony will not wear down quickly)


I'd repeat the instructions as in the previous rock, since the next one is by far the most visually appealing to me so far.

I'd however just like to point that out: Assaying is the best way to be sure. Find the outcropping and do some when you need to be sure.
Crushing and panning, however, does also greatly aid those aware that gold might be "locked up" in sulphides.
Gold locked up in sulphides needs to be crushed finely, as to liberate it. Sometimes it fails none the less.
 

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This looks real good. Metallic minerals might indeed be sulphides. I'd be out there all day for the outcrop of this fellow.
Crush and pan one piece, save the other for reference. Tippex will allow you to give it a ID-number for future reference, a little tip.
The ID-number I usually mark on a map, so I know where I found it.
 

An interesting rock. I'd try find some of it exposed in bedrock to hazard a better guess.
A pic of the exposure might even help to indicate what caused the alteration. My hunch: Fault- or shear zone.

It does appear to have been altered by hydrothermal fluids - a good thing - and to hazard a guess; might (originally) be a granitoid.
From a hunch, I'd say a half-way decent chance of interesting metals. I'd crush and pan some, as a indication if assaying might be worthwhile.

I have similar rocks from Sweden waiting for assay now. Mine came from a shear zone.
Either way, that's what I'd do.

Yes, there are both faults and shears in the area - lots of transitions between granites and schists and metamorphics - lots of evidence of hydrothermals as best I can tell

Access in some of the valleys challenging, so sampling wherever I can to narrow focus

Crusher arrives this week, and have made friends with someone who has an XRF, which should prove immensely helpful

Any idea what the metal in the core "tube" might be? Initially i'd gotten pretty excited about it, however it appears to be more silvery - although a lesser amount of tiny gold-looking nodules in a different part of the rock.

I'm (totally) guessing that the silvery ones might be some form or silver, tin, or galena? Seems a lot of black bands might be oxidized silver? (or pyrite?)
 

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Calcite will react with vinegar, bubbling and fizzling. Do the test. But the looks do have a chalcedony-ish look to it. Most times however chalcedony will not wear down quickly)


I'd repeat the instructions as in the previous rock, since the next one is by far the most visually appealing to me so far.

I'd however just like to point that out: Assaying is the best way to be sure. Find the outcropping and do some when you need to be sure.
Crushing and panning, however, does also greatly aid those aware that gold might be "locked up" in sulphides.
Gold locked up in sulphides needs to be crushed finely, as to liberate it. Sometimes it fails none the less.

Thanks EU - Maybe vuggy quartz?

I was thinking of using Aqua Regia to remove any gold from the crush pulp - any tips on whether to run it through a different acid first to take some of the other metals out before aqua regia?

I'm also thinking that I will want to XRF these before deciding which way to go? I couldn't get back to the area this weekend, but ITCHING to get back up there this week if I can!

This looks real good. Metallic minerals might indeed be sulphides. I'd be out there all day for the outcrop of this fellow.
Crush and pan one piece, save the other for reference. Tippex will allow you to give it a ID-number for future reference, a little tip.
The ID-number I usually mark on a map, so I know where I found it.

Thanks!!
 

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Yes, there are both faults and shears in the area - lots of transitions between granites and schists and metamorphics - lots of evidence of hydrothermals as best I can tell

Access in some of the valleys challenging, so sampling wherever I can to narrow focus

Crusher arrives this week, and have made friends with someone who has an XRF, which should prove immensely helpful

Any idea what the metal in the core "tube" might be? Initially i'd gotten pretty excited about it, however it appears to be more silvery - although a lesser amount of tiny gold nodules in a different part of the rock.

I'm (totally) guessing that the silvery ones might be some form or silver, tin, or galena? Seems a lot of black bands might be oxidized silver? (or pyrite?)

Indeed. Both shear- and fault zones can cause mineralization. Sounds like fun to me!

Nope, I'd not dare hazard a guess at what sulphides or metals are present. Pyrite is almost always present, however.
The reds and some yellows are likely caused by iron oxides. I see something resembling mica in there to.

XRF measures a very small surface area, so beware of its limitations. You're gonna need a lot of individual test points to get a average.
 

Thanks EU - Maybe vuggy quartz?

I was thinking of using Aqua Regia to remove any gold from the crush pulp - any tips on whether to run it through a different acid first to take some of the other metals out before aqua regia?

I'm also thinking that I will want to XRF these before deciding which way to go? I couldn't get back to the area this weekend, but ITCHING to get back up there this week if I can!



Thanks!!

Do you know how to safely use acids/chemicals? If not, leave it be. We're not talking metals here, but often sulphides, equals toxic fumes.

Gravity methods will get you quite far, actual assay the rest of the way. XRF can be used as further indication on what route to take.
 

Indeed. Both shear- and fault zones can cause mineralization. Sounds like fun to me!

Nope, I'd not dare hazard a guess at what sulphides or metals are present. Pyrite is almost always present, however.
The reds and some yellows are likely caused by iron oxides. I see something resembling mica in there to.

XRF measures a very small surface area, so beware of its limitations. You're gonna need a lot of individual test points to get a average.

Yes - just want to asses some of the interest spots on the rocks, to kind of determine what is present and how to deal with

One concern I have are the formations I've circled here, which have more than a passing resemblance to the fern-like patterns I've seen associated with arsenic in pictures online (or Silver?)

ArsPoss1_InkedDSC00079_LI.jpgarsposs2_InkedDSC00084_LI.jpg

Do you know how to safely use acids/chemicals? If not, leave it be. We're not talking metals here, but often sulphides, equals toxic fumes.

Gravity methods will get you quite far, actual assay the rest of the way. XRF can be used as further indication on what route to take.

Lol - high school chemistry - but I have an abiding and intense sense of paranoia which should be very helpful in avoiding all risk possible - yes, would only happen in a purpose-built outdoor space, with active ventilation and protective wear, I think

Yes, I'm hoping that the XRF could help in deciding how to deal with each case
 

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Yes - just want to asses some of the interest spots on the rocks, to kind of determine what is present and how to deal with

One concern I have are the formations I've circled here, which have more than a passing resemblance to the fern-like patterns I've seen associated with arsenic in pictures online (or Silver?)

View attachment 1422445View attachment 1422446

Those all look like one mineral replaced another during alteration.
Arsenopyrite (sulphide of arsenic) typically smells like garlic when struck with a hammer. If it does, you know what you got.
Such small sulphides simply are hard to ID because the tests (such as hardness, streak) are easier on larger specimens.

Lol - high school chemistry - but I have an abiding and intense sense of paranoia which should be very helpful in avoiding all risk possible - yes, would only happen in a purpose-built outdoor space, with active ventilation and protective wear, I think

Yes, I'm hoping that the XRF could help in deciding how to deal with each case

Up to you to decide, I use a fumehood from sheet metal and a fan; homemade. Works quite well.
 

Hey everyone I found this rock while fishing. Not sure if this looks like a tree or scales. A second opinion on it would be nice thanks IMG_1198.JPGIMG_1195.JPGIMG_1193.JPGIMG_1196.JPG


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