This article is extremely interesting ad reinforces why I will never buy Electroform or Resin Filled gold..... (link at end of article).
If the gold is electroformed over copper, how is it that it can be stamped as 14 karat?
To answer this question we need to consider the following; to market jewelry as gold filled the karat gold must constitute at least 1/20 of the weight of the metal in the entire piece. To be rolled gold plate or gold overlay it must constitute 1/40 of the weight, this would apply when a layer of gold is affixed on all surfaces by mechanical means. If the thickness of the gold is between a 1/20 and 1/40 of the total weight of the metal then the purity stamp has to be preceded by a fraction accurately disclosing the weight of the gold i.e. 1/30 14K.
When we get into gold sheathing or gold plating there are specific plating thicknesses that must be attained for marking (just for clarity 1µ or 1 micron is 1/1000 of a millimeter, 25µ = 1/1000 or .001 inch). If marked as gold plate it has to be greater than 20 micro inch or greater than .5µ, gold wash must be .175µ, to mark as heavy gold electroplating it has to have a thickness of 100 micro inches (.00001”) or 2.5µ.
As you can see marking jewelry is fairly complex and all of this brings us to resin filled jewelry.
Being the curious person I am I wanted to know just how thick the gold actually was on a piece of resin filled jewelry so I immediately went into “Destruction Mode”.
We had a piece of resin filled gold jewelry hanging around so I broke out the jewelers saw and cut it in half and what we found was as I suspected, a resin core, surrounded by copper, and covered (plated) with 14K gold. What this creates is a lightweight, strong, affordable (?) piece of jewelry. The donor bangle that was cut in half cost $100 and weighed approximately 7g total. Of course cutting this bangle in half wasn’t enough I wanted to grind, twist, polish and figure out the math.
Again to clarify, this is in no way scientific or 100% accurate these measurements are very simple and were made using basic machinist tools.
Using digital calipers and a micrometer, I measured the overall thickness of the bracelet, polished off the gold on on one side to expose the copper then re-measured to get the difference. Keep in mind that if I polished too aggressively and actually removed some copper, the measurement would be skewed and would indicate a thicker layer of gold.
As I measured with the calipers and micrometer, I verified the accuracy of my instruments by measuring a gauge block then measured the bracelet again. I compared the measurements and calculated the thickness of the gold to be somewhere around 12.5µ (my research indicates that some thicknesses of electroformed gold can be as thick as 250µ or .25 millimeters).
After calculating the thickness I want to know how much gold was on the entire piece so using a much less scientific method of measurement of which the details I won’t go into, figured the total gold weight of the piece was approximately .3g or about 1/2 pennyweight (again my method would be on the high side for the gold weight) accounting for roughly 1/25 of the entire weight.
Gold has been polished away to expose the copper base.
Also to be fair this was done with one manufacturer’s product and on one piece of jewelry. It’s unknown whether all manufacturers use identical processes rendering the same results, however I would have to believe they are very similar.
The mark on this piece is 14K over (separated by a horizontal line) Resin and I believe it needs to be viewed in the form of a fraction so the truth is that the 14K gold is a “fraction” of the piece that is made of resin. This is not easy for a layperson to understand.
Let's boil this all down, resin filled jewelry has a nic form and finish but now we know that even though it's stamped 14k (or some fraction thereof) through some minimal compliance or manipulation of the standards, it reall has NO SUBSTANTIAL GOLD CONTENT!!!
I guess you could think of it this way, if you purchase a piece of solid gold jewelry (which of course would be substantially more expensive than $100) it’s not only making an investment in your jewelry collection but you’re also making an investment in precious metals. When you purchase resin filled (Electroformed) jewelry it really is on the higher end of costume jewelry and should be considered DISPOSABLE. If it gets damaged, dented or too scratched up it can’t be polished out, it can’t be repaired, and the gold recovered through a chemical process wouldn’t even pay for the chemicals.
The Fact – it’s lightweight, has nice form and finish, and is less expensive than its solid counterpart.
The Fiction – representing resin filled 14K gold jewelry as high-end 14K gold jewelry and not explaining that the gold content is so low that it is represented as a fraction or that it is made mostly of copper, in my opinion, is nothing more than a manipulation of the metal purity standards and unfettered marketing mumbo-jumbo that is designed specifically to make customers think they are getting much more than they actuall are.
I guess the old adage “If it sounds too good to be true then it probably isn’t” applies in this case.
http://www.coldforgerings.com/14k-resin-filled-jewelry-fact-or-fiction/
*~"Never eat more than you can lift......" Miss Piggy~*