I just broke down and ordered an acid test kit for gold so I should be able to do it in a couple days. I don't really like the idea of scratching vintage jewelry though. And it requires a pretty hard scratch too if you want to make sure it isn't just plated. Seems like you could do visible damage to the item. Is my paranoia unfounded? Thanks for your replies!
It's not a big deal. Basically, you find a hidden area, on the side or the back of the piece, and rub there to create the mark on the stone. You need a delicate touch. The scratch on the stone doesn't need to be large and bold. Just broad enough so you can see the acid's reaction. When you get your kit, and you are experimenting with it, you will get a feel for how bold your rub mark needs to be. As for damage to the piece, it should barely be noticeable.
I only ever file directly onto the piece of jewellery if it is total scrap or I’ve been given permission on here!. Other than that I always use a scratch stone and as Stracci says above, pick a hidden edge to rub on the stone. Nothing makes me crosser than a nice piece of jewellery destroyed by scratches and acid damage. I’ve got a few bits that I’m pretty sure are gold but I’m not willing to dig deeper to see if it’s just plate so those remain a mystery unless I take them to a jeweller. I’m still nervous of jewellers though as some can be butchers!
It seems to me that you would have to scratch some outer protruding edge on the stone that may not be all that "hidden." Like I said I'm paranoid!
I also want to add that I love my acid test kit, and it is one of the best things I ever bought. I have many pieces of unmarked jewelry from yard sales and estate sales that turned out to be solid gold.
@Dave D , don't be afraid! You are the boss of that jewelry! On a pendant/brooch there are always edges to use. On a ring, I gently rub the side edge of the shank, never the broad side. You don't need to push too hard to make a decent mark. For a chain, just carefully hold the links and gently rub back and forth to create a mark. The mark should be roughly 20mm by 2mm. The mark needs to be long enough to accommodate 3 drops of acid. Carefully place a small drop of 10k acid on one end of the mark. If the acid eats it away, then the piece is not gold at all, or possibly 8-9k. If the acid doesn't eat it away, then add a drop of 14k next to it, but not touching. Don't let the drops run together. If the mark still doesn't get eaten away, then add a drop of 18k. When the mark stays intact under the acid, then that is what karat the item is. After testing, wipe the stone clean with a wet paper towel. And don't get the acid on your skin--it burns! You will have lots of fun testing your gold!
@Darkwing Manor The one I have is called PuriTest. But I'm sure they are all pretty good. I think I spent about $15 on my kit. It's really useful to get a kit that includes the silver test, too.
I use PuriTest as well. I only buy a new silver test bottle every year or so, they tend to go off. For those replacements I buy the cheapest I can find. (Yes, I am Dutch )
I can never read the results of the silver test acids, I rely on 18k gold acid instead. It IDs silver for me but doesn't tell me what kind of silver, so it's not for everyone.
You would probably have to spell it here as well, I have never heard the name before. Which part of the Netherlands is his family from, do you know?
I can answer that next Wednesday, when he returns from fishing....I do remember he said it was somewhere along the border with Germany, which kept moving around over time.
