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Coprolite gemstone?


Jpdigger

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Corporlite? Very gemmy with concentric red bands, some translucency like tiger eye. Dense with approx Sg of 4.

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Welcome to the Forum. Please send us clear photos from several angles and tell us where it came from and the name and age of the rocks.

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Trying again,

I was asked to identify this but I am pretty amateur. The concentric rings around the long axis are very interesting, fine grained and natural smooth polish with some translucence. Very dense with metal and a SG approximated at 4. I am getting more info on the geologic setting, but it sure looks like poop. What do you think? What in the texture helps identify a coprolite?

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Agree with tony here,the framboidal morphology gives it away as such.

Edited by doushantuo
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Since there are many dark botryoidal minerals and as a double check for hematite, do a streak test. Scratch it on an unglazed tile or the underside of your toilet tank lid. If it is reddish or reddish brown it is most likely hematite. Yellowish brown is most likely goethite.

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My goal is to leave no stone or fossil unturned.   

See my Arizona Paleontology Guide    link  The best single resource for Arizona paleontology anywhere.       

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I agree with the others, not a coprolite. Not an expert here, but it looks more like an agate to me, especially since you said it was somewhat translucent. Looks silica based. It is a beautiful rock. Nice find and welcome to the forum! :goodjob:

Edited by GeschWhat
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Do you know where this was found? It looks like some fire agates found in Arizona and New Mexico.

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...I'm back.

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Thanks for your knowledge. What surface textures help identify coprolite?

If you are talking about the agatized (siliceous) "gem coprolite" you see on-line, it is somewhat doubtful that that is coprolite at all. Surface texture can vary. What is important to identify it as a true coprolite is often what is included inside. With siliceous coprolites, often times you have to slice into it to positively identify it. You look for things like backfilled burrows left by insects such as dung beetles, plant material or bits of bone/scales. Most coprolites that can be positively identified as such are from carnivores and are comprised primarily of calcium phosphate...the same mineral found in the bones of the animals they ingest. Location is a key factor. Coprolites from terrestrial vertebrates such as dinosaurs, are usually found near bones. You want to look for things like over all shape (morphology), sphincter marks, intestinal folds, and surface inclusions (bone/scales). If you click on the link under my name, it will take you to my website, which contains numerous examples of coprolites. Keep in mind that the site is primarily for kids and immature adults. Those labeled as "dubiocoprolites" may or may not be coprolites at all. I also have a few up there that I refer to as psuedocoprolties. Those look like coprolites, but are geological.

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Very few agates exhibit black, especially for the whole piece. Fire agate is a form of chalidon and usually white with brownish banding, caused by inclusions of hematite or goethite.

The piece in question shows some red bands, this is because of the purity of the hematite. Pure hematite is red, the rest is black because of impurities in the structure.

I stick with My original assessment-- this rock is a classic example of hematite.

Tony

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Very few agates exhibit black, especially for the whole piece. Fire agate is a form of chalidon and usually white with brownish banding, caused by inclusions of hematite or goethite.

The piece in question shows some red bands, this is because of the purity of the hematite. Pure hematite is red, the rest is black because of impurities in the structure.

I stick with My original assessment-- this rock is a classic example of hematite.

Tony

I agree with Tony that this probably is hematite. Jpdigger, as a double check, rub the rock against a concrete driveway or sidewalk to get a streak. If it is red it probably is hematite and not an agate.

My goal is to leave no stone or fossil unturned.   

See my Arizona Paleontology Guide    link  The best single resource for Arizona paleontology anywhere.       

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I think Tony is right on this one. Hematite could be.

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It's an amazing find. :)

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