Many of our customers ask us how we can tell if something is gold before we do any chemical tests. Well, a lot of it is just by experience but there are a few things you can look for to help determine whether your item is made from precious metals. One of the first things we look for when sorting jewelry is whether any of the items are magnetic. There are only three ferromagnetic elements which are iron, nickel, and cobalt. If an item is magnetic it is because it consists primarily of one of those three elements which more often than not is iron. So the easiest way to sort through a lot of jewelry is to use a very strong (rare earth) magnet to weed out all the magnetic items. We use magnets out of old hard drives. Even if the item is slightly magnetic it most likely does not contain any precious metals. There are exceptions to this rule; if the item is clearly marked but is still magnetic, have an expert help you determine if it is real.
Once we have removed all the magnetic items from the pile we then look for stamps and markings on the items. Nearly all precious metal jewelry has a mark of some kind. On chains the marking is usually on the clasp or right next to the clasp and on rings the markings are on the inside of the ring. Oftentimes, people find the stamp but don't know what the stamps mean. We will go through each precious metal and list the most common stamps for different grades of gold. I am sure we will miss a few but this should help you get a better understanding of what it all means. Remember, just because it is old does not mean it is a precious metal.
Many stamps are simple to read and understand like: 10K, 14K, 18K and so on but sometimes there are just 3 numbers marked instead of a karat grade. The three numbers you might see are actually just a decimal number representation of the karat grade of the item. Since 24 karat is the most pure (24 parts out of 24 parts are gold) we can then figure out the percentage of gold in the other karat grades. So now we know a 10 karat piece is 10/24ths gold. 10 divided by 24 is 0.417 or 41.7% gold. This percentage is often marked as three numbers on a 10K gold ring, 417. The same is true for all other karat grades.