Gold Content in Gold Filled Eyeglass Frames

There have been many discussions about karat values, stamping laws, and legal requirements for items that contain precious metals. In the U.S., manufacturers have always been allowed a little leeway. Prior to 1976, manufacturers were allowed to underkarat by 1/2 karat if the piece was solid, and there was an additional 1/2 karat allowance if the piece contained solder. The allowance was decreased in 1976, but there's still a fudge factor.

I just came across an excellent example while browsing through eBay listings. Here's a photo of a package for some gold filled eyeglass frames.

Notice the two statements of quality on the package. 1/10 12K gold filled. Guaranteed to assay 45/1000 pure gold. Both statements are correct. :roll:

Here's a link to the listing: Gold Filled Eyeglass Listing

Dave

Aha! so 1 tenth of the weight will assay to a minimum of 12k?

So in effect you're looking at 4.5g per Kg? Or you have to take the 12k factor in too? Or much less? Ouch my head hurts because it's so misleading.

Alternatively I missed something Dave but was that what you were trying to show?

Jon

spaceships said:

Aha! so 1 tenth of the weight will assay to a minimum of 12k?

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Within the fudge factor that's allowed.

So in effect you're looking at 4.5g per Kg? Or you have to take the 12k factor in too? Or much less? Ouch my head hurts because it's so misleading.

Click to expand...

No, 45/1000 pure gold. You're guaranteed to get 45 grams per kilo (at least, until the first time someone starts working with them and abrading some of that gold that's on the surface).

Alternatively I missed something Dave but was that what you were trying to show?

Jon

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Gold filled is a layer of karat gold, filled with base metal. 1/10 12K means that 1/10 of the weight of the piece will be 12K (again, ignoring that nasty little fudge factor). So simple math would say that 12K is 50% gold and 50% alloying metals. Since 1/10 of the weight of the item is supposed to be 12K, simple math says you should be able to get 1/10 of 50%, or 5%. So, a kilo should give you 50 grams. But, because of the underkarat fudge factor, the manufacturer only guarantees 45 grams per kilo. Cool, huh?

The point is, you simply can't rely on stamping in the U.S. When I buy karat gold based on stamping (and testing to verify the stamped value), I always calculate my price based on 1 karat below the stamped value.

Dave

Thanks Dave 8)

(1/10)(12/24) = 0.1 X .50 = .05 = 5%. That's without the tolerance.