The number markings on precious gold jewelry are a bit of confusion to lots of people. We are generally used to seeing a karat or silver mark like this: 10K, 14K, 18K, Sterling, etc. The numbers mean the same thing.
For 14k the number is technically 583 but most manufacturers adopted the European way and make 14k gold a tiny bit over 14k, so the mark is 585 in most 14k jewelry. 18K is marked 750. If the mark is valid and there is a makers mark also in the jewelry, the number means these items are 18k gold.
Here is where the numbers come from. Pure gold is called 24 karat. For 18k gold, there are 18 parts of pure gold mixed with other metals to make the metal suitable for use in jewelry. 24k is too soft alone to stand up or to hold stones well. 18 parts pure gold divided by 24, or 18/24 equals 750. That is where the number comes from. The jewelry is 75% pure gold, 750 parts gold with 250 parts other metals out of “1000″ parts. It is easier to think of it as a percent which is pure gold in the recipe.
Sterling silver is marked 925. Sterling is 92.5% pure silver and the rest is other metal, generally copper.
What does it mean if the ring marked 14K PR? The 14K simply means it is 14K (Karat) gold and because of the K means it would have been made in either South East Asia or The United States. The PR marks are just the Maker or Store ID or even a design mark, and have no relevence to the Value.
The basic decimal formula to work out the quality of gold content is quite simple, as they are all measured in ‘Parts per Thousand.’ This means that 9ct gold is calculated like this: 9 (for 9ct) is divided by pure gold (24) and then multiplied by 1000 (for pure gold as a decimal). ie: 9/24*1000=375 That 375 is the decimal quality for 9ct gold and is sometimes shown with a decimal point in front – .375
The old Victorian standard of 15ct gold is calculated the same way – 15/24*1000 = 625 (Not quite the numbers you have on your jewelry. Dental gold is 16ct or 666 recurring. But you can also reverse this formula by starting with the decimal and working back. ie: 375/1000*24 = 9
In your case we can use 698/1000*24 = almost 17ct
I have a platinum engagement ring and found a wedding ring that I really like but the band is made of palladium. Is it safe to wear these two metals together without one damaging the other?
It will wear the softer metal OVER TIME but that could take many years. My Grandmothers wedding ring eventually wore away the band of her engagement ring but it took over 20 years to do.
Platinum and Palladium and quite good together but I would take the advice of your local friendly jeweler and have them check both rings. Sometimes the Platinum may be a lower grade in order to make it harder – so have that checked.