I think it might mean the size.
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More than likely, the 12 stamped in your ring means that it is 12 karat gold.
It is the weight usually or it's the code number of the company
6 is the number of the great Lucifer in christian scriptures.
The number inside a diamond ring refers to the carat weight of the diamonds found in the ring. A .50 stamped inside a Diamond Solitaire ring means that it has a 1/2 Carat diamond while a .97 means that it is just below 100 points or One Full Carat.
I have a white gold ring stamped 750 HG with a diamond. The dimond is real. I filed the ring shank and it still tested 18kt. gold
It could mean gold electroplated with 10K gold. And, if the band is plated, the stone is not a diamond.
Karats
DC stands for Diamond Cut.
10k 512 means, you have a 10k gold ring with 5.12carat's total gem weight.
my husband and i foun a set of gold and diamond rings.
Because it's not a diamond. Diamond rings are set in gold or silver which are stamped with purity hallmarks.
other alloy than gold
Gold and Diamond Mining
the PG stands for Plated Gold - meaning the ring is not pure 14kt gold but made of another metal overlayed with 14kt gold
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it a silver ring or gold over silver ring with cubic zar /AKA fake diamond !!!!!!!!!!!