Visual Surface Inspection
The first thing I do when a piece of jewelry comes in is, I look at it. You didn’t expect that, did you? Right off the bat, you can eliminate most of the jewelry out there. If you see bubbling on the metal, or copper/brass wearing through, that would be signs of plating. If it seems normal, I look for a stamp that tells me what kind of metal it might be. A loupe is handy to have!
Here you can see a silver plating over copper, with brass under the copper.
There are stamps that are required to be placed on a piece of fine jewelry that tells you what kind of metal it is. If it is silver, gold, or platinum, it will have a stamp.
It’s important to note that just because a piece is stamped, that doesn’t make it real.
- Silver will generally be sterling silver, and the stamp for that is 925.
- Gold has many stamps, which relate to the purity of the gold. They could be 8k 10k 12k 14k 18k 22k 24k. Really the only ones we usually see are 10k 14k and 18k. In Europe, those would be 420, 585, and 750 respectively. This is because 10k gold is 42% gold, 14k is 58.5% gold, and 18k is 75% gold.
- Platinum is marked 950. That means platinum is 95% pure platinum. Platinum jewelry costs more because it is a harder metal, which is harder to work with, and the precious metal content is high.
- There are stamps that are somewhat misleading, such as “14K HGE” “14K GE” “14K GF” “14K Rolled Gold” These are all plated. Also, any fractions involved with the stamp mean the piece is plated, such as “14K 1/20”
We have strong magnets. They are called Neodymium Rare Earth Magnets. They’re not expensive, get a pack if you check jewelry a lot. Gold, Silver, and Platinum are not magnetic. Interestingly, I have come across some sterling jewelry that is slightly magnetic. It is usually Mexican jewelry, but it passes the acid test. This just means that the jewelry is mostly silver (sterling is 92.5% silver) but there is some iron in the mix. Most jewelry manufacturers don’t use iron in their alloys.
So, 99% of the time, if the jewelry sticks to the magnet, it isn’t real.
The Acid Test
This is the final test. We waded through the 100s of fake pieces, now we have a small pile of potential gold. For this step, you need a black testing rock and some testing acid. You can get a kit for $25 online. You lightly scrape the piece on the stone, and it will leave a line. You pick the acid that matches up with the mark on the piece. If the piece doesn’t have a mark, you will have to make a few scrape lines and test it with multiple acids. For gold, if the line stays solid for 30 seconds, it’s good. If it fades, it could be a lower gold content, so test it with a lower acid. If it still fades or burns away, it’s no good.