Anybody Have A Clue On What This Might Be?

[jasong]

4 hours ago, Tom T said:

The mill is a “Mighty Mill”, I only run it a couple seconds to pulverize just about anything to powder, because it’s powered by a cheap angle grinder from Harbor Freight that spins at about 7,000 rpm. Looking at the balls, they look like they were fairly spherical before they were released from the rock because they all have small indentations which I would expect. The rocks were found (I was told) in woods creek in Jamestown Ca. Just west of Sonora…. The graphite photos are interesting… 

That's an impact mill. They create little balls out of anything malleable because it will not powder and thus just roll around inside as the chains push them around. I've run many tons of gold ore through impact mills, it all comes out in sphere even though it's definitely not spherical in the ore.  

Graphite is brittle (naturally occurring stuff anyways) and is not a metal. The chances of it emerging from an impact mill intact that was run long enough to crush quartz/feldspar butnot powdered a graphite is close to zero. You flattened it with a hammer too which means it's malleable. Put a propane torch to one of those spheres for 15 or 20 seconds and see if it melts, that's where I'd start. Lead should melt within that time frame easy. 

Are you sure someone didn't shoot the rock with a shotgun while aiming at a bird or something, and there was lead embedded in/on it? That rock looks like a diorite, and as I mentioned earlier, it's not really a typical ore.

I would try to eliminate lead first, and then go from there.

[Clay Diggins]

10 hours ago, Tom T said:

The rocks were found (I was told) in woods creek in Jamestown Ca. Just west of Sonora…. The graphite photos are interesting… 

I doubt the sample is dolomite marble with that location. I'm with jasong - it's probably diorite.

Considering the location Chromite comes to mind but Chromite is brittle and wouldn't form balls.

The chain flail mill design is kind of a cheap hack with a lot of drawbacks including balling malleable ores. The better choice is a hammer mill but when it comes to budget the chain flail mill is much less expensive for small batches.

[Tom T]

I’m pretty sure it’s lead…gonna torch it later this afternoon.

[GB_Amateur]

I don't think the small graphite pieces ("balls") will sound off on an IB/VLF although I'm not sure about what happens with 50 kHz and up frequency detectors.  Try a 'lead' (actually graphite) pencil to confirm.  Large graphite loaded rocks will hit about the ferrous -- non-ferrous breakpoint on an IB/VLF and even cause a handheld pinpointer to sound off, but I think the pulse decay is fast enough that a PI will remain silent even with those.  Both graphite and metals will read zero ohms on a multimeter so that won't distinguish.  However, if it shows resistance then that would likely rule out all of the above.

[Tom T]

14 hours ago, jasong said:

What kind of mill, impact mill? If so then the mill itself will turn anything malleable into tiny bb-sized balls as a result of the chain/flail rotating everything around inside. Seem like lead from your description.

Great information… I’m new to the hard rock thing and have saved everything I’ve run through it. That little tidbit is gonna shorten the learning curve substantially…thanks