How can i tell if it is gold and how pure?

Question

I came across some old large magnetic motor starters and the contacts on them appear to be a gold type alloy or something and i know gold is used in high end electronics for its certain properties. So how about it does anybody have any insight.

Answer 1

Gold is very soft and has a gold streak when given the streak test.  (pyrite has a dark green streak). Cannot be oxidized and only certain rocks brear it such as quartz. most gold, when found, is in it's purest form. 24 karats.  usually ranking about a 2.5 on the Moh's scale

Answer 2

The purest form of gold is very soft.  The softer it is the more pure.  I believe 24 carats is the purest form of density that can be manipulated and stablized.

Answer 3

Gold is often used for contacts because it is highly conductive (more than copper) and it does not oxidize or tarnish.  It is very resistant to corrosion, as well.  Unfortunately for you, a thin layer of gold, measured in thousandths of an inch, is sufficient to confer these benefits.  So there is not much gold in any one contact.

Extracting the gold from the contacts and purifying it will take some doing, you might talk to a gold scrap dealer.

Grandpa

Answer 4

bite it...

gold will squish

pyrite won't squish

Answer 5

..mm..  gold alloy is hard to refine back to pure gold, so the worth suffers sharply due to the chemistry and process of refining.

But if you have quite a bit of the alloy it may be worth the expense.

Try this... if you know of a smelter any where you can borrow, rent, beg, bum or commandeer, melt your lode of alloy at a starting temp of 2500 degree, if it wont melt at that temp, increase the temp until the melt turns white hot, [and note that temp...that will give you an idea what is alloyed with any gold in your find] scrape the top of the ladle off, let the casting cool, then check your casting for 'layers' of color...

The gold would be on the bottom, the next heaviest metal on top of it, and the next heaviest on top of that.

By the way, .. a torch wont be enough... you need to melt the whole lot of alloy to a temp that is the additives melting temp, so the

metals will separate from one another.

Gold melts at around1700 degrees, but copper, nickel, tin, iron, and so on all have ther own melting temps, so your smelter would have to reach there individual temps ...

  That's sorta why it's expensive to 'refine' alloy gold.