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FossilsFossil or Artifact?

12th Jul 2023 13:53 UTCTracey Northutt

An expert in Indian artifacts is baffled by this stone. It was in a storage unit purchase in Iowa. So actual origins are unknown. measures appx 9"x 7"L x 2.5H. Fairly heavy for size.

Thank you

12th Jul 2023 13:57 UTCDavid Von Bargen Manager

Is the rock hard or soft?

12th Jul 2023 19:53 UTCTracey Northutt

opposite side. it is hard. From this view it looks like (petrified) wood.

12th Jul 2023 16:13 UTCEd Clopton 🌟 Expert

It appears carved vs. naturally formed, but it's hard to imagine for what purpose. The rock resembles dolomite or limestone from eastern Iowa (I spent my first almost 50 years there), but it also could be from a great many other places. To verify the rock type, try scratching off a bit from an inconspicuous edge onto a plate, gather up the powder, add a drop of vinegar, and watch closely for bubbles to form. Bubbles = carbonate mineral, probably calcite; no bubbles = something else. And if you can't scratch off any powder with a steel knife point, it's too hard to be calcite (which is what limestone is made of).

12th Jul 2023 19:56 UTCTracey Northutt

opposite side. it is hard. From this view it looks like (petrified) wood.

The stone is at my friend's house, but I feel possibly limestone.

I tend to agree that is purposely carved. Too exact and uniformed to be from nature.

13th Jul 2023 03:31 UTCKeith Compton 🌟 Manager

I don't believe it is carved.

Ripples for example, in sedimentary rooks are common enough (if it is a rock).

Your comment "Too exact and uniformed to be from nature" !! You need only look at pyrite cubes from Spain to disprove that comment (admittedly different to a sedimentary rock).

But you really need to provide more info on the piece - hardness in particular, test with vinegar and/or acids etc.

26th Oct 2023 00:54 UTCAmanda Perry

Search images of large mammoth teeth. That is what comes to mind when I see the pattern, and the wood-grain pattern you are seeing can oftentimes be mistaken for wood when it is actually bone.

If it is indeed a large mammoth tooth, it is considerably weathered. Regardless, still a cool find!

26th Oct 2023 04:36 UTCJohn Christian

Not a Mammoth tooth. Maybe part of a mill stone with grooves.

26th Oct 2023 09:50 UTCRui Nunes 🌟 Expert

Likely a fragment of an old stone with these common grooves, used for handwashing clothes.

26th Oct 2023 12:17 UTCEd Clopton 🌟 Expert

Known in English as a "washboard". Hadn't thought of that possibility, but the scale is exactly right, very close to the ridges on mass-produced tin washboards. This is what someone seeking to reproduce one of those at home for free (except for a lot of labor) might come up with. Plenty of metamorphic boulders in a range of convenient sizes are present in most of Iowa as glacial erratics.

The fact that the ridges are at roughly a right angle to the foliation texture of the rock argues against the ridges resulting from natural folding--there is no hint of corresponding compressive deformation on the unworked reverse side of the rock.

26th Oct 2023 13:09 UTCSteve Ewens

Rui and Ed,

Great detective work!

While I am unable to remember the term, we often see things based on our own experience and background.

A great reminder of the need to keep an open mind in our pursuit of science.

Steve

26th Oct 2023 13:50 UTCJames Catmur

My thought was some form of metate, but I am not sure that would work well

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