Determining amount of gold in gold/quartz nugget

[TerryC]

Here is the way you can figure the amount of gold in a gold/quartz specimen without destroying the specimen. It is not exact but close enough to be the industry standard (close enough for us recreational miners). Your scale needs to have an accuracy of at least .1 gram, have a "hook" for hanging your specimen in air, and the capacity to handle your specimen's weight. If your scale does not have the ability to hang your specimen in air, you can easily make a "rig" to do so. Weigh the rock on the scale (dry). We will call this the "air weight" A. Record your answer! Now prepare your rock to weigh it wet. Set up a very thin piece of copper wire with a 1/4 inch loop at one end. Leave the other end straight for now. The wire must be long enough to be able to suspend your rock from the hook into a container that has enough water in it to completely cover the rock while suspended. "Zero" your scale with the wire included. Remove the wire from the hook and, using the straight end, wrap the rock once to securely hold the rock. Cut off any excess wire. Put the wire/rock back on the scale hook, suspending it in the water just enough to submerge the rock in the water. The water container is not being weighed. It must be physically seperate from the weighing platform and rock.Weigh the rock wet and call the results W. Record this answer. Now it is time to use a calculator. Multiply "W" by 3.1. Multiply "A" by 1.9 . Subtract A from W. The answer is the weight of gold in the rock in grams. Now go back to the weights you first recorded. Subtract the gold weight from the original dry weight. The answer is the weight of quartz in the rock in grams. I am not sure this method is good on gold/any-mineral rocks. Now go out there and get busy! TTC

 

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[wghome33]

Awesome I'm Definatly trying that

Thanks

 

[Hoser John]

This is the very rough formula for general results and good only for quartz only matrix. Use a graduated cylinder and measure the volume of water displaced by the specimen. If the dry weight is less than 2.7gm this method cannot be used(next to zero content) and also copper matrix is 8.96,iron based 7.87, nickel 8.9,lead 11.34 and so on. Too much to type=I'll scan and post for most accurate results later as with todays prices extreme accuracy is necessary-post later as outta time-John WOW 3 TRIES IN 3 FORMATS-FORUM WOULD ONLY ACCEPT pdf?? ANYHOW JUST MO' INFO FOR A BIT BETTER ACCURACUY-oops sorry for caps

 

[TerryC]

This is the very rough formula for general results and good only for quartz only matrix. Use a graduated cylinder and measure the volume of water displaced by the specimen. If the dry weight is less than 2.7gm this method cannot be used(next to zero content) and also copper matrix is 8.96,iron based 7.87, nickel 8.9,lead 11.34 and so on. Too much to type=I'll scan and post for most accurate results later as with todays prices extreme accuracy is necessary-post later as outta time-John

Very good, John. Very good. I use this method because I do not have a graduated container yet. I will watch for your post. Tnx. TTC

 

[TerryC]

( edits were made to original post) Thanks to your post John, I was able find errors in my original post. I now believe it is correct. Bad memory, I guess! TTC

 

[bug]

I didnt understand how your suspending the rock on the scale. I've seen it done this way before, by setting a piece of wood across blocks for the scale to sit on. Then use a clothes hanger and tare out the weight of the hanger and string, which the rock hangs from.

 

[TerryC]

I didnt understand how your suspending the rock on the scale. I've seen it done this way before, by setting a piece of wood across blocks for the scale to sit on. Then use a clothes hanger and tare out the weight of the hanger and string, which the rock hangs from.

View attachment 753641

NICE! I've seen it done that way. Although string can be used, it has a certain amount of bouyancy and may trap air bubbles if used dry. Both will cause some amount of error. Here are the two scales I have and the way they will be set up. TTC