Author Topic: Help Stone coins (Read 7277 times)

Tanit · « **on:** April 08, 2019, 07:29:56 am »

Here are two pieces that look like coins. They are stone. They were found buried underground with several hundred others of the same type. The first measures 20 mm and weighs 2.11 gr. The second measures 35 mm and weighs 5.78 gr. Both are less than 1 mm thick.
Does anyone have any idea what it is?

Thanks

djmacdo · « **Reply #1 on:** April 08, 2019, 08:06:02 am »

Yes--they are just stones--no clear signs of having been altered by human hands.

Tanit · « **Reply #2 on:** April 08, 2019, 10:06:43 am »

Quote from: djmacdo on April 08, 2019, 08:06:02 am

Yes--they are just stones--no clear signs of having been altered by human hands.

It seems to be cut to have this circular shape. And then six hundred stones at the same place and with almost the same shape and size can not be a coincidence. I think they served either as prehistoric coins or as elements in the making of a mysterious object of Roman technology.

*Alex · « **Reply #3 on:** April 08, 2019, 10:14:55 am »

They look like some kind of fossil to me. I am quite sure that they aren't coins though.

Alex.

Tanit · « **Reply #4 on:** April 08, 2019, 10:21:11 am »

Quote from: *Alex on April 08, 2019, 10:14:55 am

They look like some kind of fossil to me. I am quite sure that they aren't coins though.

Alex.

Indeed, it is possible that they are fossils of a flat marine animal with a circular shape.

Jochen · « **Reply #5 on:** April 08, 2019, 11:24:26 am »

Hi Tanit!

From the archeological or geological stratum they were on, can you tell their age?

Jochen

Tanit · « **Reply #6 on:** April 08, 2019, 12:17:15 pm »

Quote from: Jochen on April 08, 2019, 11:24:26 am

Hi Tanit!

From the archeological or geological stratum they were on, can you tell their age?

Jochen

Hi Jochen !

I do not know much about geology. I will present them at a paleontology forum. A paleontologist can surely say which fossil it is.

Tanit · « **Reply #7 on:** April 08, 2019, 01:46:27 pm »

The stones are transparent as the pictures show

Robert_Brenchley · « **Reply #8 on:** April 08, 2019, 04:52:10 pm »

Not many stones are translucent. They look like bits of chalcedony or similar. What were the rocks in the vicinity? I don't think they're fossils, but they could be natural concretions which formed in, say, limestone. The flat shape is a bit unusual, but I can't think of anything else.

Mark R1 · « **Reply #9 on:** April 08, 2019, 06:13:44 pm »

Where were they found?

JBF · « **Reply #10 on:** April 08, 2019, 07:42:06 pm »

amber in a deteriorated state??
I have heard that if you burn amber it smells like pine. Which is what it is, millions of years old tree sap. But they may be too heavy for that. Should be able to test it without lighting one on fire.

Tanit · « **Reply #11 on:** April 08, 2019, 07:53:38 pm »

Quote from: Mark R1 on April 08, 2019, 06:13:44 pm

Where were they found?

Underground in a mountain in Tunisia

Tanit · « **Reply #12 on:** April 08, 2019, 07:56:06 pm »

Quote from: JBF on April 08, 2019, 07:42:06 pm

amber in a deteriorated state??
I have heard that if you burn amber it smells like pine. Which is what it is, millions of years old tree sap. But they may be too heavy for that. Should be able to test it without lighting one on fire.

It's not amber, it's stone.

I presented these pieces in a forum of paleontology: all say that they are not fossils

Lee S · « **Reply #13 on:** April 08, 2019, 08:00:18 pm »

I remember from many years ago that there was a theory that flint is a fossilised firm of prehistoric sponges or sitting similar.... Perhaps a group of fossil ancient sea creatures?

JBF · « **Reply #14 on:** April 08, 2019, 10:16:55 pm »

Not enough information to judge. Figure out what the material is, talk to a geologist or mineralogist. Then after figuring out the material, try to account for the form. A geologist might be able to tell you why it is formed in that way too. I don't know what form they were found, but I think that you are assuming that it must be artificial because it strikes you as unusual. Of course, it may be artificial but I don't think that we (I) can judge based on what little description there is. A mountain in Tunisia is not very specific. Was it buried, a cave, a mine? Are the 'chips' consistent with the geology of the mountain or would they have to come from somewhere else?

Look up Moh's scale. It is a scale of hardness, and you should be able to find out what scratches or is scratched by what. That can eliminate some possibilities. Enough that you could tell the hardness to some geologist online when showing him it. The fact that it is translucent also says something. There are other mineralogical tests that you can look up.

n.igma · « **Reply #15 on:** April 08, 2019, 10:35:30 pm »

Looks like they are fossils of worn mollusc shells, probably from an ancient shoreline accumulation. If so then they are composed of calcite (CaCO3) and will dissolve in acid - test one. Alternatively you can test the hardness of one. Calcite is soft (Mohs hardness of 3.0) and will be readily scratched with an iron nail or by a steel blade, even a copper coin (hardness 3.2) should slightly scratch the surface.

cmcdon0923 · « **Reply #16 on:** April 09, 2019, 12:21:05 am »

The closest thing I've ever heard of that comes close to "stone money" are the Yap stones (Rai) of Micronesia.

n.igma · « **Reply #17 on:** April 09, 2019, 05:37:03 am »

Now that's what I call pocket change!

Tanit · « **Reply #18 on:** April 09, 2019, 08:48:37 am »

Quote from: n.igma on April 08, 2019, 10:35:30 pm

Looks like they are fossils of worn mollusc shells, probably from an ancient shoreline accumulation. If so then they are composed of calcite (CaCO3) and will dissolve in acid - test one. Alternatively you can test the hardness of one. Calcite is soft (Mohs hardness of 3.0) and will be readily scratched with an iron nail or by a steel blade, even a copper coin (hardness 3.2) should slightly scratch the surface.

I tested with acid. The acid stays on the surface and does nothing. I tried to pierce the piece with a needle: impossible to make even a small one hole.
What is intriguing is the large number of pieces found in the same place as a treasure and with a larger piece of about 30 cm on which is engraved the portrait of a Roman man in profile. I will post the picture as soon as the person sends it to me.

*Alex · « **Reply #19 on:** April 09, 2019, 10:09:14 am »

What a pity that you never mentioned the large piece with the portrait on it before. Perhaps your discs are counters or gaming pieces.

Alex.

Tanit · « **Reply #20 on:** April 09, 2019, 10:28:43 am »

Quote from: *Alex on April 09, 2019, 10:09:14 am

What a pity that you never mentioned the large piece with the portrait on it before. Perhaps your discs are gaming pieces.

Alex.

I think it is prehistoric or Roman flint blades used to cut or scrape.
I made the test: I cut with this tool a branch of soft wood.

*Alex · « **Reply #21 on:** April 09, 2019, 11:36:02 am »

Quote from: Tanit on April 09, 2019, 10:28:43 am

I think it is prehistoric or Roman flint blades used to cut or scrape.
I made the test: I cut with this tool a branch of soft wood.

They seem awfully small for that.

You mentioned the piece with the portrait on it. were there any other objects found along with these items? Also, "inside a mountain" is not very informative, were they found in a cave or somewhere man made like a tomb or a shrine? Did the objects look like they were placed there, perhaps in a bag or box that has long since rotted away or were they just scattered all over the place on the floor? I think that the archaeological context is going to be important in determining what these discs might be.

Alex.

Tanit · « **Reply #22 on:** April 09, 2019, 11:52:41 am »

Hi Alex!

I will try to get all this information from the person who found the pieces and I will post them as soon as I get them.

v-drome · « **Reply #23 on:** April 09, 2019, 02:58:07 pm »

What kind of acid did you use? To me these look like the natural product of a marine geological environment. If there is no wear on the edges, they were not used as cutting blades.

n.igma · « **Reply #24 on:** April 09, 2019, 05:00:29 pm »

Quote from: Tanit on April 09, 2019, 08:48:37 am

Quote from: n.igma on April 08, 2019, 10:35:30 pm
Looks like they are fossils of worn mollusc shells, probably from an ancient shoreline accumulation. If so then they are composed of calcite (CaCO3) and will dissolve in acid - test one. Alternatively you can test the hardness of one. Calcite is soft (Mohs hardness of 3.0) and will be readily scratched with an iron nail or by a steel blade, even a copper coin (hardness 3.2) should slightly scratch the surface.

I tested with acid. The acid stays on the surface and does nothing. I tried to pierce the piece with a needle: impossible to make even a small one hole.
...

Then likely to be silica (SiO2) replacements of the original calcite. Quite common in the fossilization process and well attested to in Moroccan fossil assemblages.

News:

Author Topic: Help Stone coins (Read 7277 times)