How do you know if a coin or bar is real and pure gold?

Question

I've been looking at some gold coins and gold bars. What do I need to look for to make sure they are pure gold?

Answer 1

Well, I guess if you wanted to, you could weigh them and then figure out the volume.

Density = Mass/Volume

For example, if you had a block measuring

40cm3 and weighed 454.4 kg, you would know its fake, because its density would be 11.36, and thus be lead, not gold.

If the density is 19.32, it's gold. Unless someone mixed a denser metal with some other heavy metal in such a ratio that it is 19.32.

This is just a suggestion, you should ask experts.

For measuring objects, you can use a ruler, or if it is irregular, you can drop it in a graduated cylinder and measure the displacement of water. 1 ml of water is equal to 1 gram of water is equal to one cubic centimeter.

Answer 2

When you get a bar gold bullion it comes in a sealed container for each piece - referring to 1oz (this denomination will fit in your wallet).  Every piece has been assayed.  If you open it it will need to be re assayed.  The bars are also from one of a handful of mints.  Each par has its' own serial number, and forging mint stamped on it.  Coins are a little different.  1st the are usually around 90% to 92% pure gold vs 99.9 % for a bar.  2nd you are buying the artisty, and people's desire of a particular stamping.   If they do not come in an assayed protective sleeve - then you need to have them assayed.  Gold is more difficult to sell if the item has been removed from its' protective assayed sleeve.  Shipping is pretty easy - the US Postal service takes high value items.  According to one of the clerk's '... the loss or mis-placement of a highvlaue insured item is one of the only ways to lose your job ...' at the Post Office.

Answer 3

Bars probably would need to be assayed to be absolutely sure of the gold weight and purity. Coins are exactly what they say they are -- unless someone has forged them (doubtful).