Copper Spanish cob? Need an ID

[mangum]

A couple friends & I stumbled on an early site yesterday (early for our area). My friend found this copper coin. I assume its a Spanish cob of some sort. Im hoping someone may be able to provide an ID & possible date range. I can see a 7 & possibly a 31. I did a search & didn't get a good match. Maybe it's a period counterfeit? I would appreciate any help! Thanks!

 

[GatorBoy]

I'll take your word for it but I've seen strange things happen to very old silver especially if they were near other metals that were deteriorating and putting minerals into the surrounding soil.
Nice find by the way

 

[GatorBoy]

Looking closely I can't find even a hint of green but I do see black showing underneath

 

[FreeBirdTim]

Looking closely I can't find even a hint of green but I do see black showing underneath

The simple solution is to run your coil over it and see what it reads. Even my cheap Ace 250 can tell the difference between copper and silver!

 

[GatorBoy]

Its not that easy unfortunately I have found cobs myself that read surprisingly low I have one that reads like a nickel.. Right in the middle of the midtone range.
Hundreds of years in the ground or water can change things.. Those machines with target ID aren't reading what the material is they're just reading the conductivity ..the conductivity can change due to a lot of different reasons

 

[GatorBoy]

This one reads a 56 on an AT Pro

 

[Charlie P. (NY)]

'S'true. Detectors don't know silver from gold from copper. They know ferrous from non-ferrous and everything eise is based on parameters programmed into them for relative conductivity of nice, round coin sized objects. Cobs are not typical thicknesses or shapes. They don't produce the nice eddy currents on their surface like perfectly round coins will. A 3¢ silver also reads 54 to 56 out of 99 possible on my F-75. That's less than copper or zinc US cents. Most copper coins fall between the upper and lower ends of silver coins.

Believe the little icons on your detector and you'll probably never find the neat little 3¢ coins, flying eagle cents, $2-1/2 gold or "fatty" Indian head cents. They will all show "pulltab".

 

[FreeBirdTim]

Believe the little icons on your detector and you'll probably never find the neat little 3¢ coins, flying eagle cents, $2-1/2 gold or "fatty" Indian head cents. They will all show "pulltab".

Only a fool would go by the icons on the detector. I detect by sound and it is very easy to tell the difference between copper and silver. My 1775 KG III was toasted, but I knew it was copper before I dug it. And my 1773 half real was holed, bent and worn, but I knew it was silver before I dug it.

 

[coinman123]

Only a fool would go by the icons on the detector. I detect by sound and it is very easy to tell the difference between copper and silver. My 1775 KG III was toasted, but I knew it was copper before I dug it. And my 1773 half real was holed, bent and worn, but I knew it was silver before I dug it.

I agree, My metal detector's icons and numbers may be inaccurate or unreliable. I listen to the sound. My detector may say "Silver" but have an odd sounding short almost clicking noise, that almost always means that it's a bracket. I know that tombac buttons, 22 caliber casings, small copper buttons, some shotgun shells, small gold coins, small gold in general, shredded cans, and other things show up as foil, believe it or not, for every 100 foil signals I dig out only 10 are foil. Pull tabs, Fatty indians, flying eagles, some colonial coins, some small silver coins, most gold coins, larger gold, shotgun shells, some brass buttons, and many other items. Just because an item says "foil" does not mean it's foil (which most may know) Like I said, sound can be helpful, if I hear a shallow extremely short high pitched noise that says silver, it's never silver.