can anyone help identify this rock?

critter27

Tenderfoot
Oct 8, 2011
9
0
Central Wisconsin
Primary Interest:
Metal Detecting
I found the rock in the attached photo in my yard in Central Wisconsin. I have had no luck identifying it myself, so I looked for help on line. It has been suggested to me to have an Earth Sciences or Geologist look at it to help me. I have taken it to a lapidary shop. Unfortunately, the owner was unsure of what it is, but wanted to cut it open.
The rock is very heavy for it's size. It weighs 38 pounds. It is a grayish color, but has a bluish tint when it is wet. It has an approximate diameter of 21" -22". It is a little over 12" long. An earth magnet sticks to it with no problems over the entire area or sliding anywhere on the rock's surface. It was suggested to scratch it on some ceramic to see what color streak it leaves. I did this twice. One left a blackish-gray streak. The other, from a different area of the rock, left a reddish-brown streak. When I run the earth magnet across the surface, small powdery bits stick to the magnet (almost like small shavings). I have run my metal detector over it and it gives me the following read outs: iron, aluminum/ zinc, and coins (silver or copper pennies pre 1982).
Some of the suggestions I received are: galena, limonite, iron ore, or meteorite. No one seems to know for sure. Any help you can give me would be greatly appreciated.
 

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Bum Luck

Silver Member
May 24, 2008
3,482
1,282
Wisconsin
Detector(s) used
Teknetics T2SE, GARRETT GTI 2500, Garrett Infinium
Primary Interest:
All Treasure Hunting
Well, I'm no geologist.

You're from Central Wisconsin so it's glacial - origin to your northeast towards Lake Superior. The nearest source for rocks of this type is the North Shore. Most external features that would help ID it are worn off.

If it is magnetic it has iron in it. That's also indicated by the red brown streak and the density.

I've seen a LOT of rocks as a construction surveyor, like a couple of hundred acres of 'em at a time, and I'm constantly on the lookout for interesting rocks. But, I've not seen one exactly like this. It looks like common Niagara dolomite, but it's not.

I'd saw it.
 

OP
OP
C

critter27

Tenderfoot
Oct 8, 2011
9
0
Central Wisconsin
Primary Interest:
Metal Detecting
Thank you ,Bum Luck..for the guess, all though I'm hesitant to cut into it ,it is looking more and more that way,I'm running into brick walls with this thing ,and trying to contact some one from a "earth science" field is difficult.
 

Bum Luck

Silver Member
May 24, 2008
3,482
1,282
Wisconsin
Detector(s) used
Teknetics T2SE, GARRETT GTI 2500, Garrett Infinium
Primary Interest:
All Treasure Hunting
No luck yet?

Take it to the nearest UW geologist and ask him. Stevens Point, Oshkosh, Madison Geological museum, Burnie's rock shop, etc.

PM me when you find out.
 

NowandThenTreasures

Full Member
Jul 23, 2014
190
458
Wisconsin
Detector(s) used
Garrett AT PRO, Minelab Equinox 800, Garrett Ace 350, Garrett Pro-Pointer AT
Primary Interest:
All Treasure Hunting
Did you ever find out what kind of rock this is?
 

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