more discrimation = less gold look

[Alimo88]

I actually know this answer @marcomo
I will provide a short list below
silver 629
copper 597
gold (pure) 425
aluminium 376 (aluminum) (har har)
zinc 169
nickel146
high brass (yellow) 140
platinum 94
tin 90
lead 48
All figures multiplied by 10[sup]-6[/sup] or .000001 and is in Ohms per centimeter

From the rubber bible or from Handbook of Chemistry and Physics. C.R.C. Press, Cleaveland, Ohio.

 

[rick in mi]

Thanx JC

 

[Jackpine Savage]

Those figures are for standardized sizes and temperatures.

Where gold reads on a detector depends on purity (alloy) and size (mass). A honking 24 Kt gold ring will read above zinc while a thin small cross section ring in the smaller sizes will read much lower, possibly around the nickel range. Add the various alloys 14K, 18K ect along with varying sizes we find and there is not set value for gold.

Gold rings are typically alloyed with silver and copper which have higher eletrical conductivies than gold, however the resultant alloy actually reads lower than either metal in pure form.

Tom

 

[Alimo88]

I didn't say it did

it's a chart or conductivity per cm for those that may be interested.

in my opinion all information has relevance. it how you choose to use the information.

 

[Alimo88]

Actually the chart has the utmost relevancy. Many metal detectors work on the principle of measuring the R[sub]X[/sub] signal or the received signal. A metal (generic) object in the T[sub]x[/sub] or transmitted field creates eddy currents within the metal. The difference in T[sub]x[/sub] and R[sub]x[/sub] signals is computed by the circuitry and an electronics assumption is made on the object being detected. The physical reason for different amounts of eddy currents being created is the metals conductivity. I put it to the forum that the chart is in fact very relevant. Sure other things come into the equation like size, shape, alloy, depth etc, but the bases is Physics and that doesn't change. Anybody have a detector that knows what the object is? No! My 30 year old White's 6000D works on the same Physical principles as a brand new whatever detector. If you don't understand "A" is sometimes hard to get a full understanding of "B".
I'm willing to learn, so anybody that knows why an alloy can read significantly lower than the two materials it's constructed of , please let me know.

 

[dahut]

...all information has relevance. Its how you choose to use the information.

You are right - the chart is not the end all, but it does add to the overall lore. I found a platinum ring last season and it landed well below nickle - which corresponds to the chart.

But, the one bit of information that has the most relevance is the following:

To conduct the tests, they used 161 gold rings from four collections. They passed each ring across the coil and noted how it read. The results were interesting:

Iron 0
Foil - 38%
Nickels - 9%
------------------------------------Round tabs - 15%
Square tabs - 29%
Zinc pennys - 5%

The remaining 4% were in the coin range, and of very low karat grade.

Tom is right, in that absolute electrical physics isn't as important as the information above. WHAT a ring is made of isnt as important as where to find it...well, until you go to sell it, that is!

 

[gazn357]

Alimo88,

Is your unit of measure correct? 'Ohms per centimeter' would be for resistivity. Sounds like everyone is talking conductivity.

SI unit is Ohms/meter for resistivity and Siemens/meter for conductivity. Sometimes you see "mhos" for conductivity.

 

[Alimo88]

the numbers are correct, and are conductivity numbers. Correctly stated, conductivity is the inverse of resistivity

all numbers correct but you should apply this information "Conductivity at 20 degrees Celsius, Ohms[sup]-1[/sup], Cm [sup]-1[/sup]"

I forgot the -1 bit

SORRY

 

[Hombre]

For instance..........more gold jewelery is lost at a water environment, lakes, seashore, river party sandbars etc.Just use a underwater detector at these places and dig all 'hits'. You will be amazed at you success rate!

 

[wltdwiz]

your correct location is the key
more rings in the water for sure
heres a few water finds

[attachment 158482 bhidring7.JPG]
[attachment 158483 azring1.JPG]
[attachment 158484 RINGS1.JPG]
[attachment 158485 ZEPHERCOVE2.JPG]

the charts under discussion her in this thread are a good rule of thumb but nothing beats getting out & knowing your detector.
i hunt jewelry & focus on jewelry so i find a good amount in & out of the water

[attachment 158486 BATCHORINGS.jpg]
good hunting all
walt