We have found a very unusual stone. Here's what I can tell you about it. It was found on an old farmstead in Montana in what is known to be an old riverbed. There are many other stones that look just like this one, but this is the only one that has the marking. The square shape appears to be solid stone, so I don't think that the stone had a rusted piece of metal laying on it or something to discolor the surface. Does anyone have any idea what may have caused this? If you have any geologist friends please have them take a look at the pictures. Thanks.

Close up.



Overall view.



Side view.



Randy Pepprock
Dioramas Plus

Randy,

You may have just discovered proof of visits to our planet.

If not that, a meteor fragment from distant space and proof of
alien life out there...

Seriously,

Cheers,
Joe

Yep.

well, the only thing in a rock that can have this shape is crystal I think, they always form geometrically. If lava cools slowly, crystals can form (like in granite) if it cools quickly you get no crystal and you get basalt. If this stone is originally perhaps an old seabed, it could be a fossil shell, but I have never seen a square shell.

If it is proof of alien life, there should be an unmarked van with lots of antennas on the roof in front of your house by now for 24 hrs a day.

hmmm

maybe someone needed a rock to put under a leg of a camp table and then left the table on it for 40 or 50 years and caused the rock to imprint with the square shape..

just something to toss into the pot

Delbert

It could be some sort of mineral salt or quartz structure. It looks to be igneous in origin, maybe rhyolite, and is pretty unique. You could test it but that might destroy the structure. It is certainly one to add to the collection. I'm not an expert and my knowledge is very basic, but I am an avid rock collector. My wife puts my finds in a dish on the living room table.

It does look like quartz or basalt. This is reinforced by the cross section. I'm thinking that it is quartz. From what I've seen of other quartz, it appears to be the same mineral.

A professor from the local university said "My guess is that the mineral is either a chemically zoned feldspar (plagioclase) or a feldspathoid – with nephaline being the likely mineral species."

He has not examined the stone in person, only the pictures.