i found this rock on my grand parents farm years ago, was wandering if anyone knew why it had square notch in it? some say it was a property marker to indians used it to poor candy sugar cubes.....any idea? was found on corner of property...........kev
It looks to me like there was a mineral there, possibly pyrite or feldspar that eventually weathered out or oxidized out. It left the shape of the crystal in the rock. This isn't uncommon, but I suppose it looks freaky to someone who isn't always looking at rocks.
Gold is where you find it......isn't everything where you find it?
That's why I picked pyrite and feldspar. Both can be square crystals.
I hope either of you are still on here. This is the only pic I've found online that looks like a couple of rocks that my son has found.. except, along with the empty squares, there are also some still filled with what looks like iron (?). Its definitely a metal and not one of the two crystals mentioned above, but why would they be square? There are multiple squares in a random pattern, not touching each other on each rock? The rock, itself, looks like the one pictured above (we live in Maine if that helps).
A square is a two dimensional object.
A four sided crystal would look like a three sided pyramid.
A cube has six sides.
Look for minerals that have a cubic or four sided columnar crystal structure.
You got a lot to choose from.
I have found quite a few of these rocks as well as what fell out of the holes. It may not be the same mineral but worth mentioning. These photos are from samples taken from Lamoille County VT. I only kept the cubes and not the host rock. They are not affected by a magnet.
Magnetite. Only need to check the cleavage to make sure. It should be octahedral. The color indicates it is not pyrite. The area from which they came has no known sulfur (required for pyrite).
Magnetite is strongly attracted to a magnet: you report that these are not attracted to a magnet. Magnetite almost never (if ever?) occurs as isolated cubes as seen in the photos, whereas this form is very typical of iron pyrite. The colors in the photos are consistent with weathered pyrite, the weathering is why they fall out of the host rock.
Magnetite is tough and hard, whereas pyrite is a lot easier to break or crush. If you break open one of the cubes, you'll almost certainly see gradation of color from the exterior to the interior. The discolored "rind" is probably mostly goethite pseudomorphed after the pyrite.
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Originally Posted by EggyOG
