If Buying Gold Bars, Also Buy ...

For a 10 oz bar, the difference of weight between tungsten and gold would only be 0.9 grams. Cover the tungsten in a layer of real gold, and the difference is smaller. I bet the weight made the short list for which bars to drill, however. A good scale to three decimal places would be a start...

Also, tungsten is weakly magnetic. If you get a powerful industrial magnet on a string, or a swing magnet that geologists use in the field, you might be able to detect it...

Personally, I rely on the smell test for determining if my silver is fake or not. If it smells like clean sweet distilled water, it is real but if it smells like acetone or something acidic, it's most likely to be fake. In addition, drop tests work wonders too.
I would like to point out that there have been MANY Sunshine Minting Silver Bars circulating on sites such as ebay and I've been a victim, I bought two bars and smelled them, they both smelled like acid so I instantly knew they were fakes and got my full refund, several days later the seller got bombarded with many negative feedbacks.

Indeed it is. Most of us would not want to be drilling holes in any of the PMs we own, nor would be like the idea of a buyer wanting to do that before buying an item we have for sale. From what I understand, the sonic test is not specific for gold but it just happens that most metals have different sound propagation velocity through their atomic matrix. Some of them are quite close, though, such as tin and gold. Tin is a lot lighter than gold, though, so a specific gravity test should eliminate the use of tin as a gold contaminant.



Yes, an XRF detector can do a very good job of detecting gold in various alloys (14k, 18k, etc) and should be able to differentiate gold plated items from solid gold items. It is not usually a cheap device, though... maybe $500-1000 or more for the unit in the video. I went to their web site. There is a lot of info there but no prices that I saw. I noticed that they do lease these units, though, which indicates that they are expensive. It doesn't usually pay to lease something that is cheap.

The beauty of the sonic detector is that the technology in it should be cheap. All it needs is an ultra-sonic sound generator, a timer, and a signal detector. The generator sends out a pulse, the timer starts running, the signal bounces back from the other side of the metal, and the timer stops. By knowing the length of the metal and the time the pulse took to travel through the sample, a speed in meters per second can be calculated. A very basic on-board computer could handle these steps. I have not seen such a unit for sale anywhere but I am pretty sure that they are out there somewhere. There are lots of portable ultra-sonic thickness gauges, so one of them might also read out in m/s. If it did, then all you would need is the speed and a chart of speeds for various metals to determine if you had pure gold or a gold + something else mixture. An even simpler test for specific gravity would be needed to see if the gold item in question was of about the right density to be gold, although tungsten can fool this test. Combining the results from the two tests should give the best results by eliminating the potential interference from tin (sound test) and tungsten (spec. grav/test).

UPDATE!

Apparently, the good folks at Gold Money have a very sophisticated ultra-sound machine that has technology that is similar to that used in medical applications. This is not a cheap hand-held unit but it seems to work amazingly well. So well, in fact, that Gold Money is advertising that ALL of the gold held in their vault is tested with this machine and that they consider this good enough to be proof of authentic gold bars, rounds, and coins. See here:

http://www.youtube.com/watch?v=rh0Mcagio5Q

I saw that too, they were having a hard time justifying the price but ended up trying it out or something. Never have seen they using it though, wonder if they do.

Yeah, don't we just wish! The paperwork at Ft. Knox might be real interesting to a forensic accountant as well.



. When I started looking at this, I was hoping to find a small unit that would be in the $100-200 range. At that price, a lot of bullion and coin collectors could afford to have one. I am still searching. Will update if anything of interest turns up. If not, I may need to get into my workshop for some development.

This is really scary. I have been buying silver till now and was thinking of buying some gold. I do see some good deals for gold locally in CL but I have not done anything yet. My biggest concern is how to be sure it is real. I am not a jeweller and I cannot tell gold if I see it. I can try to but american eagles or maples but even they can be fake. What is an easy way to find if it is actual gold?