Large river rocks in California gravel bar triggering signal, what are these?

[firebird]

I went metal detecting for the first time today with a cheap metal detector in Briceburg near Yosemite, along the Merced river. Didn't find anything interesting aside from trash but it does work. One odd thing I noticed though is that some large rocks are also producing a signal, like that biggest rock here at the bottom of the picture. Wasn't able to get a closer picture, but it's just a large, dark colored rock that didn't look particularly special but was really heavy and large, only a sledgehammer would be able to break it open.



Why would it be producing a signal, are these rocks full of iron concentrations large enough to set off the metal detector? I spend my time here just panning for gold instead since there are small flakes here and there but there's also a huge amount of black iron sand.

 

Amazon Forum Fav 👍

Family Maps of Hinds County, Mississippi, Deluxe Edition - Grab it through Amazon!

[dognose]

Dont know about the rock.

That is a beautify location.

Did you find any gold?

 

[galenrog]

Many rocks contain detectable metal ores. One of the most common is iron. These are commonly referred to by detectorists as “hot rocks”.

Time for more coffee.

 

[pat-tekker-cat]

Was just going to say, "hot rocks".

They were all over Bondi Bch, Au, too,
very frustrating little boogers...

I'd double check it with the sledgehammer, though,
just to be sure....

GL & HH.... (yes, a beautiful looking location)...

 

[firebird]

Thanks for the info, I have much to learn from metal detecting still, just got it this Christmas as a present. There is gold here but only really tiny flakes in the gravel, it just seems to be a waste of time metal detecting since the gold seems to come from all the way in Yosemite and just grinds down to tiny pieces that a metal detector can't find. Here's a nice overhead view of the area here.

 

[A2coins]

What reading did your detecor give

 

[A2coins]

Welcome from Mi. Tommy

 

[pat-tekker-cat]

You may get more info out of the prospectors section/sub-thread.
I mine gold, too, just in a different manner, opposite coast...
I'm usually scratching around in a litter box.

Them hard core prospectors would prolly laugh
at anything us beach fellas tell ya.

I did run across this today (on fb).
That's about my level of panning/sluicing/etc...
Even though I don't speak the language,
I can see what they're saying....

It is for learning sake, (somewhat)informative, none the less.
And cute...

https://www.facebook.com/goldlineor...8WNYj5BVlfMnVdg51MIDFuR6zzgqtfTLS02pYDAYwESWy

 

[Tanneyhill]

Thanks for the info, I have much to learn from metal detecting still, just got it this Christmas as a present. There is gold here but only really tiny flakes in the gravel, it just seems to be a waste of time metal detecting since the gold seems to come from all the way in Yosemite and just grinds down to tiny pieces that a metal detector can't find. Here's a nice overhead view of the area here.

Go for a hike upstream Merced and the creeks that flow into it if you are interested in big nuggets.