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AU testing?

CladiatorCladiator Posts: 18,050 ✭✭✭✭✭
in Precious Metals
Other than weighing and measuring are there any ways to determine the authenticity of gold coinage? Perhpas a device or tool that can test the purity of the metal without damaging the coin?

Comments

  • gecko109gecko109 Posts: 8,231 ✭
    All I know of is the acid test which, as you know, involves scratching the piece. Careful weighing and measuring is always a surefire way to see if the coin is of gold composition. However, that may not be enough to authenticate a specific coin.
  • CladiatorCladiator Posts: 18,050 ✭✭✭✭✭
    I thought there was some type of electronic device that could tell you the metal type. Bummer.
  • OPAOPA Posts: 17,124 ✭✭✭✭✭


    << <i>I thought there was some type of electronic device that could tell you the metal type. Bummer. >>



    check with a PCGS coin grader ... they might know
    "Bongo drive 1984 Lincoln that looks like old coin dug from ground."
  • DeadhorseDeadhorse Posts: 3,720 ✭
    Specific gravity testing, as opposed to simple weight and measurement(volume), used with chemical reactions is the standard assay tool.

    Now, if you can afford an electron microscope................... well anyway, that's a bit over the top, but it would be interesting.

    An electron microscope would give you the perfect assay and I'm sure it has been used somewhere, at least occasionally I'd think, on precious metals.

    "Lenin is certainly right. There is no subtler or more severe means of overturning the existing basis of society(destroy capitalism) than to debauch the currency. The process engages all the hidden forces of economic law on the side of destruction, and it does it in a manner which not one man in a million is able to diagnose."
    John Marnard Keynes, The Economic Consequences of the Peace, 1920, page 235ff
  • mercurynutmercurynut Posts: 3,207
    Yukon Cornelius (Rudolf fame) use to just lick it and tell its purity. Give it a try and see if it works.
  • gecko109gecko109 Posts: 8,231 ✭


    << <i>Specific gravity testing, as opposed to simple weight and measurement(volume), used with chemical reactions is the standard assay tool.

    Now, if you can afford an electron microscope................... well anyway, that's a bit over the top, but it would be interesting.

    An electron microscope would give you the perfect assay and I'm sure it has been used somewhere, at least occasionally I'd think, on precious metals. >>




    Wont a microscope only show whats on the outer most layer of the object? If a lead piece was coated very thickly with pure gold, how is a microscope going to help to determine its composition?
  • gecko109gecko109 Posts: 8,231 ✭
    Got a spare $1500 Cladiator? Try this out!

    gold tester


    Or this one for just a deuce

    another gold tester
  • CladiatorCladiator Posts: 18,050 ✭✭✭✭✭
    Damn, had no idea they were that expensive.
  • DeadhorseDeadhorse Posts: 3,720 ✭


    << <i>

    << <i>Specific gravity testing, as opposed to simple weight and measurement(volume), used with chemical reactions is the standard assay tool.

    Now, if you can afford an electron microscope................... well anyway, that's a bit over the top, but it would be interesting.

    An electron microscope would give you the perfect assay and I'm sure it has been used somewhere, at least occasionally I'd think, on precious metals. >>




    Wont a microscope only show whats on the outer most layer of the object? If a lead piece was coated very thickly with pure gold, how is a microscope going to help to determine its composition? >>




    Well, define outermost at the electron level.

    Basically, you are correct, but it would be able to see several electron levels into the metal.

    Slice samples could be prepared for analysis.

    Mostly I was referring to the "electronic device" that Clad was talking about.

    It would be interesting to see the electronic viewed composition of silver, gold, uranium, etc.

    Each would have it's own unique identifiers.
    "Lenin is certainly right. There is no subtler or more severe means of overturning the existing basis of society(destroy capitalism) than to debauch the currency. The process engages all the hidden forces of economic law on the side of destruction, and it does it in a manner which not one man in a million is able to diagnose."
    John Marnard Keynes, The Economic Consequences of the Peace, 1920, page 235ff
  • fcfc Posts: 12,793 ✭✭✭
    there is a story back in the gold rush days where a crook took a rock
    and plated it with gold. it was a very pretty appearing nugget
    and quite large.

    well the crook took it to be assayed and knowingly had an area that
    was a divot into the rock that had a thicker coating of gold.

    he told the assayer to dig in that "special area" as not to mar the
    beautiful specimen. Well the assayer comes back and says it is
    very pure..

    and the crook procedes to immediately sell it on the spot to a person
    who was amazed at the size and shape... as a crowd often gathers
    to look at such specimens.

    it sold for quite a sum. the crook was long gone when they found out
    the ruse.

    fun stuff. ;-)
  • clouisejewelersclouisejewelers Posts: 329 ✭✭
    Nothing works better than the acid test. I don't like the electronic testers, they are not very accurate in my opinion.

    It's pretty easy to tell real gold from fake with a little experience. After you master that you can learn to tell 10K from 14K from 18K from 21K by the heft and color of the piece.
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