How much platinum in this ring?

[MGH]

Hello GRF,

I’m looking for some help on properly identifying this platinum ring. This came from a co-worker’s wife from whom I buy scrap jewelry from time to time. This is the first time we’ve dealt with any platinum. I’m looking for some help in understanding the real platinum content so I can make a fair payout (I haven’t paid anything yet, but said I would pay 85% of the platinum content).

The ring is completely unmarked. It doesn’t look like there were ever any markings; no excessive wear or filling. It passes the platinum acid test on the stone. The gemstones were removed before it came to me, so I don’t know what was in there.

I took it to a local gold buyer with an XRF and it shows as somewhere around 87-88% platinum, with Iridium the next most abundant, and I just can’t recall what it showed after that. I’ve seen that platinum jewelry may be alloyed at 85%, 90%, or 95%. I’m wondering if one of these is most likely, or if it’s most likely that it really is somewhere around 87%.

I don’t know everything about this buyer’s XRF. But I’m pretty sure it’s set up with one calibration which he uses to test everything from silver, to karat gold, to bullion (unless it has an auto-read feature I’m not aware of). Has anyone else encountered a similar situation? I want to buy the piece if for no other reason to have a little platinum on hand (though I may also look to trade or sell it later), but I want to pay a fair price – neither unwittingly cheating nor overpaying. It weighs 6.71 grams.

Thanks,
Matt

 

[solar_plasma]

what is its specific gravity/density? As long as it is no intentional fake with a tungsten core, the density may give a good hint about the content

 

[Harold_V]

Not to be taken as gospel, but the most common alloy I found, by a large margin, was 90% platinum, 10% iridium.

Damned shame the stones were removed from that ring. Pretty good chance it would be worth far more as jewelry.

Harold

 

[solar_plasma]

You could buy new stones, they are not necessarily expensive.....well, I would do just that and use the ring as a present to my girl:

http://www.eurogem.biz/de/shop/Diamant/1.html

 

[MGH]

Thank you both. It would probably be agreeable if I were to pay as if it were 90%. Then if it was really only 85%, I'd still a little cushion - a tiny bit.

I'll have to see if I can set up to do a specific gravity analysis. Yes, too bad the gemstones weren't there!

Thanks again.

 

[Anonymous]

I'd go lower mgh, but I will agree with Howard here- that is worth a lot more as jewelry.

 

[goldsilverpro]

As with Harold, most I've seen is 90Pt/10Ir. In the late 90's, 95Pt/5Ru gained quite a bit of popularity with some jewelers but many I talked to didn't like casting it. I don't know what is happening nowadays. I think 95Pt/5Co is popular in Europe. It's said to have excellent casting characteristics and it's probably cheaper.

 

[solar_plasma]

Put a cup filled with water onto a weight. Set the weight to 0g. Let the ring hang in the middle of the water. Measure the water displacement: 1g water=1cm³. Set the weight to 0g again. Now let the ring sink to the ground and weigh again.

Divide the second value with the first value and you get the ring's density.

Compare it with the alloys in the table:
http://www.ganoksin.com/borisat/nenam/jewelry-platinum-alloy.htm


I just wondered how this method could be improved and I got some ideas: The second value (exact weight of the ring) could have been measured at first without water. The volume of the part of the line under water can easily be calculated and substracted from the measured displacement in any case, if you use fishing line with known thickness.

 

[Anonymous]

Akk I meant Harold of course! My typing hand wasn't clever last night.

 

[Dan Dement]

Harold is dead on as usual. The ring probally was made in the 20"s or 30's and metal of choice was 90Pt/10Ir. I manufacturer Platinum and Palladium jewelry and am on my fourth XRF. SG test is not going to help you. I agree the ring is in very good shape but would take a great deal of labor to restore it to make wearable. I don't think a dealer is going to pay more than metal. Most rings of this age have been worked on with white gold soldier as using a torch to retip would cook the diamonds or stones. To restore, you either have to do all the work before setting the stones or have a very talented jeweler with a good Laser welder.

Dan

 

[joubjonn]

my wedding band is platinum. it says PT950 inscribed. love my wedding band, I know a lot of men these days get the carbide bands which is fine, saves a lot of money, I just wanted something a bit more special.

 

[FrugalRefiner]

my wedding band is platinum. it says PT950 inscribed.

Which means yours is 95% platinum, 5% other metals, for anyone not familiar with the hallmark.

Dave

 

[MGH]

Excellent information. Thank you gentlemen. Maybe I'll look for a jeweler who would be able to recondition the ring themselves, and be willing to pay at least spot price for the metal.

 

[joubjonn]

vintage ring like that, you might get more. I would even go so far as contacting someone that specializes in vintage jewelry. it might be something special even without the stones

 

[solar_plasma]

why so comlicated. Heat it, set matching stones into it and let it cool again. You could try with cheap circonias for a few cent first.

 

[nickvc]

Looking at the ring it seems that some of the settings claws are missing and with the cost of retipping and setting its scrap, many items of jewellery with larger stones become what is known in the trade as breakers,purchased with the idea of doing just what has been done with this ring, remove the stones for resale and scrap the mount.

 

[MGH]

I took the ring to a local jeweler to ask his thoughts (and was willing to sell if it was worth any more than scrap value to him). He does a lot of custom work in his shop and routinely works with platinum. He agreed that the ring was 20’s – 30’s vintage, but also agreed with the general consensus here that it would not be worth putting as much labor into as would be required for resale.

For now, I went ahead and purchased the ring under my standing agreement with the seller. I don’t have any immediate plans for this ring, so I will probably be listing it in the Sale or Trade section. I’m open to offers and will put more details there. At the very least I can hold onto it for a while and then sell to a larger volume buyer if the platinum price goes up some more, or I may just hold onto it in case I want to get into some platinum refining in the future.

Thanks again everyone.
Matt