This report from Jim Willie, of the Hat Trick Newsletter, puts some good perspective on the rumors circulating about counterfeit gold bars filled with tungsten with new details...

In October, the Hong Kong bankers discovered some gold bars shipped from the United States were actually tungsten with gold plating...The initial discovery was something like four gold bars, which the Hong Kong bankers drilled invasively to test the contents. Reminds me of drilling the earth and measuring how many grams of gold per tonne. The HK bankers hoped to have 99% gold yield in their drill program for the resident bars. They found something like 1% instead and 99% tungsten.

...and now that people's suspicions have been raised...this is the best test you can do and while it is destructive, you know for a fact you are getting what you paid for...

Now not a single assayer on the planet is available, as all are tied up. They have been commissioned to test the gold bars shipped from the United States of Fraudulent Banker America in their own bullion vaults. They use basic methods of four drill holes with direct assay of shavings, but also less invasive methods like electro-magnetic waves to examine the metal lattice structure. When highest level methods are needed, they turn to mass spectrometry. NOW ALMOST NO GOLD BARS WILL LEAVE THE LONDON OR NEW YORK METALS EXCHANGES WITHOUT SOME AUTHENTICATION, AS DISTRUST IS WIDESPREAD.

...not a lot of facts are available at this point, but if you are purchasing "good delivery" 400 ounce COMEX bars, be sure to get your own assay on delivery.  Why would someone commit this kind of fraud -- other than the goal of making money?  Throwing the gold markets into disarray is going to be part of the complete economic takedown we see on the horizon.  If people can't trust gold, what will they trust?