[rctee]

I have an old (about 60 yrs.) white gold wedding band marked "18kt P". Could anyone tell me what the "P" indicates? Thanks.

[tickle]

Could stand for platinum which is white as opposed to yellow gold. Platinum is valued higher.

[bentrade2]

THE “P” MARKING IN THE JEWELRY.
The markings in gold jewelry sold in the USA should meet the standards of Federal law. The marking “P” is part of that and as you suspect, does not mean platinum. Platinum is marked with “plat” or “pt” in most cases, often followed by a number showing the platinum content.

Before 1981 jewelry manufacturers were allowed to be about ½ carat off compared to the mark they placed in jewelry. What this meant was a ring stamped 14k could actually be 13 ½ k or up to 14 1/2k. Of course, manufacturers were easily able to make jewelry which was 13 ½ k pretty consistently and doing that saved them gold.

In 1976 a law was passed to require jewelry makers to be much closer in gold content to what the karat stamp said. Gold had to be within a very close tolerance of 0.003(three one thousandths) of the karat mark on the jewelry. The law did not go into effect until 1981.

In the meantime, jewelers made efforts to change to the new quality control. There was one problem: How would customers know which ring was 13 ½ karat ( made before the law was effective) and jewelry made to the new standard? Put two rings side by side and both would be marked 14k, for instance. One would be the older 13 ½ karat version and the other would be the actual 14k version! Who could tell the difference? Manufacturers did not want confusion with customers and also wanted to promote jewelry made to the higher standards and looked for a way to distinguish the older jewelry from the newer.

The answer was a mark of a “P”, like in the ring you described or the word “plumb” stamped along side the karat mark. When customers saw the “p” and it was explained what it meant, they knew this jewelry met the new standards for accurate marking of the karat. Have you heard of a plumb bob? This is a heavy piece of metal (generally) shaped like a fat carrot with a point at the bottom. The plumb bob hangs from a string. When the string is held up at the top of a wall with the bob just at the floor, the line made by the string is straight up and down, right on the mark. Carpenters can use the plumb bob to find a straight up and down line for construction work. “Right on the mark” is the idea behind using the word plumb in marking gold after the 1981.

Tara, back then much jewelry on the market was made before all manufacturers converted to the new “plumb” standard and the P or plumb mark was used in new jewelry. A lot of time has passed since 1981 and jewelers have dropped the “P” from the stamping. Today, the 14k mark may be taken to mean just what it says, on the mark and really 14k.
Hope this helps!

[runningbrook57]

18KP would mean 18 karat plumb, which is 'exactly 18k gold'

[SunStar Babe]

Likely, which would be a bummer, it is 18k Plate.

[runningbrook57]

If it were gold plate it would say 18KGP.

[runningbrook57]

If it were gold plate it would say 18KGP.

http://www.legacyfinejewelers.com/this-a-that/54-selling-your-gold/83-not-all-that-glitters-is-gold.html