QuestionI have an absolutely amazing antique lava cameo - truly the finest carving I've ever seen - very unique. It's like a 3-D statue coming out of the stone. So, it surprised me that it appeared to be set in a gold plate frame. There is a place where the inside edge is bent, and the gold - which tests at 22K - has literally flaked off - I saw a flake, and can see a line where it has flaked before. It was blackened under the gold, like tarnich, but when I scratched it with my fingernail, the black came off to reveal what looks like rose gold. I cleaned the black off - I figured it was copper, but the 14k gold test acid doesn't react to it - actually, all it did was remove even more of the black discoloration. And, oddly enough, it has been soldered in four places on the back with what looks like lead - it's kind of graphite colored, but very hard. Also, the clasp is clearly Victorian, open c, with a hinged pin - the door-hinge type. The stationary part that's soldered to the brooch is gold, but, the pin itself, and it's hinge section, is silver colored. It doesn't look silver or gold - I thought it was stainless steel, maybe, but it does not react to the acid, either. I know the acid is good - I've tested dozens of items, but this one has me stumped. Any ideas? I'm at my wit's end!
Thanks!
Shan
AnswerShan, well done high relief cameos are something I do appreciate and only rarely see fine one. Once in a while we have a customer bring in a nice Victorian or Edwardian cameo for repair, generally because of a broken pinstem.
I note that often we see previous repairs on these items and the solders are just as often of a gray color like lead solders but harder, more like silver solder. Sometimes the pinstems are sterling and not gold, likely a replacement or possibly(I really don't know about this) originals.
A surprising amount of older jewelry including cameos and other items will combine sterling with gold. Sterling is sometime the back of the item with gold settings, layered in a way.
While the finer ones are indeed gold, many less costly versions and repros are gold plated. From what you say and the acid test results, yours appears to be gold plated over a lower karat of gold. I would have to do the test personally to be certain. The solder could be a silver solder of some unknown mix and over time could certainly develop the gray coloration. Lead solders are rather easily scraped with a sharp tool and easily revealed.
There is always a chance you acids are weak and not giving correct results but you said you know the acids are good. So, if you have not tried a side by side test try this: Do you have some known gold with which to compare acid test results? That comparison can answer a lot in a hurry with a scratch test and is needed more than looking for a reaction only from the acid directly on the metal. A slate stone works for the rubbing block to rub a bit of metal from the unknown and the known sample side by side then apply acid to those rubbings. Reactions are fairly quick in such thin rubbings.
I doubt the pinstem is stainless, not because of the acid test but because of the design you described, a sort of "door hinge" which is indeed an older style. My suggestion is to test the pin and see if there is any discoloration, grayish color, white coloration spot on the metal, etc., which could reveal the stem is silver. Silver is a likely candidate but testing may rule that out. If not silver, knowing it should not be stainless, then we are left with a high karat white gold or even platinum. I would opt for the high karat white gold first, thinking it could be a replacement of the original. Who knows what has happened to the cameo from original day of manufacture to today? That part is a mystery.
I am no expert on period jewelry, please keep that in mind. What I have said will likely not solve your situation of the unknown pinstem, unless it is silver or a karat of gold not reacting to your 14k test acids.
I wish I could provide you more info. Please do get back with a "follow-up" if something more comes to mind.
God Bless and Peace. Thomas. July 22,2007 4:02PM
