Many people do not realize that all gold is not the same nor will it respond the same. If you look at a conductivity chart, you will see gold in pure form has a conductivity of about 70 on a scale where copper is 100.
http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/
Now, take pure gold and add a little silver and copper and what happens? Well, that very conductive gold can easily go from a 70 down to 20 or so, which is quite close to lead.
What does this mean to someone using a TDI and trying to figure out the best setting? Well, in simple terms, it means it really helps to know how the gold where you are hunting might respond. Very pure gold less than 1/4 oz will almost always create a high tone or act like a low conductor. Less pure gold may always act like a low conductor no matter the size or quantity. So, in pure form, most likely a 7 gram nugget will still act like a low conductor but an 8 gram might go either way if it is very pure. In areas where the gold is not pure, even a fist size nugget might respond as a low conductor.
Of course, there are an infinite other possibilities between the two extremes, so it is not easy to say for sure just what you should expect without first testing gold from the area.
Reg
http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/
Now, take pure gold and add a little silver and copper and what happens? Well, that very conductive gold can easily go from a 70 down to 20 or so, which is quite close to lead.
What does this mean to someone using a TDI and trying to figure out the best setting? Well, in simple terms, it means it really helps to know how the gold where you are hunting might respond. Very pure gold less than 1/4 oz will almost always create a high tone or act like a low conductor. Less pure gold may always act like a low conductor no matter the size or quantity. So, in pure form, most likely a 7 gram nugget will still act like a low conductor but an 8 gram might go either way if it is very pure. In areas where the gold is not pure, even a fist size nugget might respond as a low conductor.
Of course, there are an infinite other possibilities between the two extremes, so it is not easy to say for sure just what you should expect without first testing gold from the area.
Reg
