RARE -- CHAPTER 7 -- COUNTERFEITING GOLD

CHAPTER 7 – COUNTERFEITING GOLD

In this chapter, the author recounts stories of metal counterfeiting.  The desire to turn metals into the more precious metal gold has been around since the time of alchemists.  He starts off the chapter telling the successful story of Seaborg and collaborator to transform bismuth, a less precious metal, to gold.  High energy collisions in a particle accelerator between bismuth atoms and neon and copper atoms succeeded in removing 4 protons from several hundred bismuth atoms to turn them into gold atoms.  Probably the most interesting recent story of counterfeiting, according to the author, is based on reports of drilling tungsten into gold bars to pass them off as pure gold.  This counterfeiting method worked because gold and tungsten have very similar properties in terms of densities and heat capacities but different colors (tungsten is grayish white while gold is yellow).  The best tool to detect counterfeits turned out to be high precision balances that can detect small differences between the mass of a bar of gold and the mass stamped on the gold surface.  The author noted that an ultrasound device should be able to tell the difference between a pure gold bar versus a tungsten bar coated with gold: the speed of sound in tungsten is almost twice that in gold.  The author also delved into instances of counterfeiting coins.  He first discussed the difference between the cost of producing the coin (or bank note) and the value of the currency which is referred to as seignorage.  At present prices, the copper penny and nickel cost more to make while the dime, quarter, and dollar coin cost less to make.  A net gain in seignorage provides motivation for counterfeiting coins although, for modern coins, this is not an easy thing to do.  Back in Roman times, the non-uniform shapes of coins made it easy to cut a piece off unnoticeably without changing the nominal value of the currency.

o   For the penny, this comes out to 1 penny net loss for the government ; that is, it costs 2 pennies to produce 1 penny.  Pennies created after 1982 only contain 3 percent copper from 100 percent before.  (The process requires melting zinc and a little copper, parceling it out into discs, stamping the image, and transporting rolls.)

o   For the nickel, it is an 11 cent net loss for the government.

o   For the dime, about 6 cents net gain.

o   For the quarter, 11 cents net gain.

o   For the dollar coin, a net gain of 21 cents.

o   It costs the same to produce a nickel and the quarter.

·         During the era of the Roman Empire, coins were not uniformly circular so it was easy to remove small amounts of gold and silver without changing the value of the currency.

·         Mark Antony used coins in which some copper was mixed in with the silver.

·         Modern coins are harder to counterfeit.

·         The author believes that much of our knowledge of modern chemistry and metals arose from alchemy.  They also invented many of the equipment (e.g., crucible) and basic laboratory techniques such as filtration, crystallization, and distillation.

·         In 1980, Seaborg and collaborators succeeded in removing 4 protons from an atom of Bismuth (Z = 83) to convert it to gold (Z = 79) by bombarding bismuth atoms with copper and neon atoms producing several hundred atoms of gold.  As the author points out, this energy-intensive process is not an economically feasible, to say the least, way of producing gold.

·         Tungsten and gold have very similar properties:

o   tungsten and gold of the same mass will have very similar volumes because of their almost identical densities (differ by 0.2%)

o   their heat capacities are within 5% of each other so “human touch would not feel an appreciable difference between the two metals at room temperature”

·         but they also can differ in other properties;

o   tungsten is grayish white and gold is yellow

o   the melting point of tungsten is 4000 F points higher than that of gold

o   gold is twice as efficient as a heat conductor compared to tungsten

·         Coated with a gold layer, tungsten can be a believable stand-in for gold.  Reports of counterfeit gold using tungsten have been reported in China, Australia, and New York City.

·         Tools used to check for counterfeits:

o   High precision balances to check the mass against the inscription on the bar

o   Portable x-ray fluorescence detector

·         The author proposes the use of an ultrasound device:

o   The speed of sound through tungsten (17,000 ft/s) is nearly twice that in gold (11,000 ft/s) (In air, over 1,100 ft/s)

o   Sound going through pure gold of one type of atoms is different from sound going through a sample with two different elements.

·         Seignorage = the difference between the cost of producing coin or blank notes and the value attached to the currency. 

o   For the penny, this comes out to 1 penny net loss for the government ; that is, it costs 2 pennies to produce 1 penny.  Pennies created after 1982 only contain 3 percent copper from 100 percent before.  (The process requires melting zinc and a little copper, parceling it out into discs, stamping the image, and transporting rolls.)

o   For the nickel, it is an 11 cent net loss for the government.

o   For the dime, about 6 cents net gain.

o   For the quarter, 11 cents net gain.

o   For the dollar coin, a net gain of 21 cents.

o   It costs the same to produce a nickel and the quarter.

·         During the era of the Roman Empire, coins were not uniformly circular so it was easy to remove small amounts of gold and silver without changing the value of the currency.

·         Mark Antony used coins in which some copper was mixed in with the silver.

·         Modern coins are harder to counterfeit.