Different platinum alloys

[bluemoi]

I heard some places manufacture certain blends of platinum. Here is what I have learned:

Anyone considering a platinum ring should be sure to ask for a quote in 95% Platinum / 5% Ruthenium (it is the same blend that Tiffany & Company uses) as this blend probably has the ideal mix of attributes with regard to hardness and scratch resistance. Because Plat/Ruthenium is harder to cast, many jewelers do not use this blend.

Conversely, 95/05 Platinum/Iridium blends are easier for the jeweler to cast and finish. What is not commonly known is the fact that this 95/05 blend of Platinum/Iridium is very soft and is therefore very prone to scratching and even bending/fatiguing in smaller sections or elements.

There was one that mentioned an S1/plat mix that I didn''t understand but they claimed to be very hard and more durable but not available anymore. Don''t know but maybe some of the experts can advise us of what is commonly used today and what to ask for when asking for a platinum setting. I am a newbie and still trying to understand the difference as I would like my engagement ring to be very strong and durable and really protect the diamond. What questions should I be asking? Anyone have any experience with the mixes mentioned or even a different mix I left out? Am very curious and this has got me rethinking about setting quite a bit. I don''t want to be confused when I go in to get the diamond set. I hope you can help.

 

[Erik Carlson GG]

I believe the S1 blend was invented by the late Steven Kretchmer. He pioneered many new platinum mixes.

The best thing for you blue, is to decide on a setting style and go over the different methods of manufacture for the style that you choose. As you alluded to different platinum blends will work better for certain types of manufacture (i.e. casting or hand fabrication), and the metal that you choose may not be compatable with the ring style that you love.

 

[bluemoi]

Yes I know and there is a degree of different risks to the stone with different methods and blends. I know that the softer ones are less risk to the diamond setting, but if you paid enough for your diamond, then I think it deserves something of great value and durability and wear for life......don''t you?

 

[Richard Sherwood]

Here''s an interesting rundown on the different platinum alloys by Mark Morrell:

Platinum Purity
I use "Classic" 90% platinum / 10% iridium in my work (PT 900)

I get a lot of requests for "950" platinum. I''ve been asking those who request "950" platinum - which one? - there are several - and what benefit do you desire from your choice of alloy?

The answers that I''ve received include vague mentions of "purity" as well as hardness and durability. I''d like to address some of these issues at this time.

Precious metals are generally mixed with other metals to establish their rating, karat, or numerical designation by weight. In "950" platinum, 95% of the weight of the net alloy will be platinum mixed with 5 % of another metal - by WEIGHT. Those who are familiar with the "periodic table" remember that each element has it''s own specific gravity or mass. This means that some elements are "heavier" than others. A 1" cube of one material will weigh more or less than another of equal volume. As an example of how the various weights per unit of different materials can influence an alloy or mix of different elements, please try to picture the following example in your mind''s eye.

Picture a shopping bag full of feathers and imagine the weight of this bag full of feathers. You can pack the bag any way you choose - it''s your mind''s eye, after all. Just think about this for a second.

Now, please try to picture an identical shopping bag - but this time it''s full of rocks - granite rocks, about fist size or smaller will do for this example.

Both bags are the same size. Which bag do you feel will be heavier?

If you think that the bag of rocks will be heavier than the bag full of feathers, then I believe that I''ll be able to clear up some misconceptions regarding the "purity" of "950" platinum for you.

As I mentioned above, different elements have different atomic weights. There are four commonly used platinum alloys and many more that see less usage. Let''s discuss the top four platinum alloys because these are the ones that you are most likely to encounter as you research your choices. For the record, platinum has an atomic weight of 195.078.

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1) 95% platinum (950) - alloyed with 5% iridium - Vickers hardness = 80

Iridium has an atomic weight of 192.217 - pretty close to that of platinum.

We''ll need just over 5% of the VOLUME of our platinum - in iridium - to make our "950" blend.

This is a very soft alloy - is extremely malleable - Setting stones is the least risky in this alloy. Dents and dings occur easily. Is resistant to wear and abrasion but not resistant to scratching, bending and being deformed and dented by impacts. This alloy works extremely well for both casting and hand fabrication. It just doesn''t age very gracefully.

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2) 95% platinum (950) - alloyed with 5% ruthenium - Vickers hardness = 135

Ruthenium has an atomic weight of 101.07 - a bit over HALF the weight of iridium

By VOLUME, we''ll need almost twice as much ruthenium to equal the weight of the iridium in the above "950" iridium example.

This alloy is fairly hard - resists dents and dings well - is less malleable - is resistant to wear and abrasion but prone to cracking and requires more pressure to be imposed on a stone during the setting process than the softer alloys. When it doesn''t crack, it features all of the longevity that platinum is renowned for. This alloy works reasonably well for both casting and hand fabrication - when it doesn''t crack. This is a very good alloy for machine cut parts.

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3) 95% platinum (950) - alloyed with 5% cobalt - Vickers hardness = 135

Cobalt has an atomic weight of 58.933200 = roughly only 30% of the atomic weight of platinum and iridium.

When we consider the VOLUME of this element required to equal 5% of the weight of our platinum, we need almost 3 1/3 times the volume of our iridium to generate 5% of our platinum by WEIGHT.

This alloy is fairly hard - resists dents and dings well - is not reasonably malleable or workable at the bench - is much less resistant to wear and abrasion than the iridium and ruthenium alloys - lacks longevity because of it''s LACK of resistance to wear and abrasion and will require that more pressure be imposed on a stone during the setting process. This alloy works extremely well for casting. This metal polishes quickly because polishing is "abrasion" and the alloy doesn''t resist abrasion as we''d otherwise expect platinum to do. This alloy features a natural "bluish" color cast due to the high volume of cobalt. Rhodium plating is often employed to hide it''s native color. This metal it is magnetic. You can actually pick up a piece made of this metal with a strong magnet. Welding and hand fabrication have proven to be problematic for bench jewelers / repair technicians.

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4) 90% platinum (900) - alloyed with 10% iridium "Classic Platinum" - Vickers hardness = 110

Again: Iridium has an atomic weight of 192.217 - pretty close to that of platinum.

10% iridium, by volume, is a touch over the volume of ruthenium required to equal 5% of our platinum.

By this measure (volume), 10% iridium platinum is only a bit less "pure" than 5% ruthenium platinum. 5% cobalt is miles away from being as pure as either.

This alloy is of upper-medium hardness - resists dents and dings well - is reasonably malleable - and requires less pressure to be imposed on a stone in the setting process than the harder alloys - is about as resistant to scratching as the 950 ruthenium blend and features all of the longevity that platinum is renowned for. This alloy works extremely well for both casting and hand fabrication. This is my platinum alloy of choice.

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I believe that the desire for "950" platinum is primarily driven by the fact that 950 is a bigger number than 900 - it looks better in "print" - so it must be "better". As you have read above, the "950" designation doesn''t really mean anything with regard to the "purity" of the metal. The most "pure" of the 950 alloys (5% ir) is too soft to serve the needs of my my clients properly, in my opinion.

Many folks request "950" platinum but none that I have spoken with about this have associated any tangible benefit with their request. "950" just sounds better.

Folks, my reputation, my livelihood and the welfare of those who depend on my financial support are all contingent on my making good choices in my work.

My platinum work is done, specifically, by means of casting and hand fabrication. I believe I have made the best choice of platinum alloy for my method of manufacture. Other methods of manufacture as well as manufacture on a much larger scale than mine will benefit from the use of some of the other available alloys. If my work does not perform as expected, my lifetime commitment to building an honest product is nullified. Do you really think I would make a decision as important as which platinum alloy to use in my work without having given serious thought to my options? In an effort to satisfy my client''s requests, I have worked with all of the above alloys as well as a couple of lesser known "950" platinum blends. I have even gone as far as creating my own blend of "950" platinum by mixing iridium and ruthenium in various ratios with a 95% platinum base. I did this to satisfy the "950" content while maintaining the working characteristics of my favored 90/10 iridium mix. In the final analysis, I couldn''t justify the added process of my private mix. At the end of the day, the tangible benefits of my private blend - to you, the consumer - were the same as 90/10 IR (900) platinum.

Respectfully,

Mark Morrell

Thanks to my friend - Bob Lynn - for his input on some of the technical issued addressed above - and for encouraging me to stop working long enough to write this document.

 

[bluemoi]

I just came across 97% platinum with iridium. I wonder about the hardness in this mix which is offered here in australia. I wonder if it compares to the 95/5Iri blend or would it be even softer? How safe will the stone be in that case? Thank you Richard for all your helpful information, and for your honest opinion on what you prefer.

I think for most engaged couples stone security and damage is an issue and something they want to be informed about no matter how little the risk is, the honesty is extremely respected and makes good returning customers.

 

[Garry H (Cut Nut)]

Date: 5/24/2009 1:27:07 AM
Author: bluemoi
I just came across 97% platinum with iridium. I wonder about the hardness in this mix which is offered here in australia. I wonder if it compares to the 95/5Iri blend or would it be even softer? How safe will the stone be in that case? Thank you Richard for all your helpful information, and for your honest opinion on what you prefer.

I think for most engaged couples stone security and damage is an issue and something they want to be informed about no matter how little the risk is, the honesty is extremely respected and makes good returning customers.

Bluemoi, If you are seeking sratch resistance then there are very hard nickel white golds.

A big part of the charm of platinum is that it develops a patina, and the softer the platinum, the sooner you get a patina.

 

[bluemoi]

Yes that could be an option for people who don''t have sensitive skin. However I don''t mind the patina you speak of but like I mentioned I was only curious of the different blends out there and what they offer in relation to diamond safety and protection. I was once told that it can come loose sometimes. I guess I was just searching for some assurance and that someone was going to say that all blends are of similar quality? ..........don''t know just happy to be learning. Should I not worry about the platinum blends and their differences?

Am seeking your kind of knowledge too Garry.........appreciate your professional opinion.

 

[CharmyPoo]

Not to thread jack but I am interested in hearing about any color differences with the alloy compounds. My ering is 90% Platinum and 10% Iridium. It appears grey to me beside my T&CO rings which I believe is 95% Platinum and 5% Ruthium. Thoughts?

 

[John P]

Date: 5/24/2009 8:38:31 AM
Author: CharmyPoo
Not to thread jack but I am interested in hearing about any color differences with the alloy compounds. My ering is 90% Platinum and 10% Iridium. It appears grey to me beside my T&CO rings which I believe is 95% Platinum and 5% Ruthium. Thoughts?

T&Co does use Pt950Ru. With new rings there shouldn't be a notable difference though. See below where common Pt alloys are quite close to each other, with rhodium plating and silver a bit closer to absolute white (credit Stuller for the chart).

Perhaps in your case the patina is developing faster on your Pt-Ir e-ring, thus the greyer appearance? This is possible since Pt-Ir is softer than Pt-Ru and more susceptible to microscopic nicks and scratches - which is what a patina is. If you have the e-ring polished it should restore the original appearance.

 

[John P]

Photos comparisons (new rings under diffused, color-corrected daylight normal lighting)

A: Platinum-Iridium
B: Platinum-Ruthenium
C: Platinum-Cobalt

 

[CharmyPoo]

Thank you John! That is wonderful. I actually like the look of A best in your photo.

Perhaps my ring wasn't polished well when I received it. It had that look from day 1 and there were scratches.

 

[John P]

Happy to help Charmy.

Maybe look into a re-polish for that e-ring. I have mine repo''d every few months - and it''s Pt-Ru. Of course I''m made of snakes & snails & puppy dog tails - whereas you''re sugar & spice - but our finger blingers can all use some TLC now & again.

 

[strmrdr]

my fav is 950 Platinum sterling *grin*

 

[Diamond Explorer]

Hey All,

I love it when these kinds of threads come up. There are so many great platinum alloys out there. I like 90/10 Plat/Irid too because of its strength, hardness, and bright whiteness. Plat/Ruth has a darker tinge, to the point of it sometimes being rhodium plated to make it white. The platinum alloy should be selected to best suit a particular project. I have no trouble working in just about any alloy a client prefers, but my favorite platinum is definately 90/10 Plat/Irid for its beauty and versatility.



Storm,

What more can you tell me about Plat/Silver alloy. I would think the temperature of molten platinum would be too high to easily add silver. There would definitely have to be a special technique for alloying silver in platinum to avoid vaporizing the silver

John,

In that chart you posted do you know if the PT/IR blend is 90/10 or 95/5?

 

[Moh 10]

Which PT alloy is best for tension settings?
I believe you''d want an alloy that maintains its ability to grip, or resists bending open.

Does anyone know what Niessin, Steven Kretchmer and Gelin Abaci uses?
Is their exact alloy proprietary?
I have not found it revealed on their websites, only that it is 95% PT.

 

[strmrdr]

Date: 5/24/2009 5:41:59 PM
Author: Diamond Explorer





Storm,


What more can you tell me about Plat/Silver alloy. I would think the temperature of molten platinum would be too high to easily add silver. There would definitely have to be a special technique for alloying silver in platinum to avoid vaporizing the silver

http://www.abipreciousmetals.com/Sterling%20with%20Platinum/Sterling.htm

Plat-sterling is 95% silver 5% plat.
Out of all the "white" metals used in jewelery my favorite is silver.

 

[strmrdr]

Date: 5/24/2009 5:56:24 PM
Author: Moh 10
Which PT alloy is best for tension settings?

I believe you'd want an alloy that maintains its ability to grip, or resists bending open.


Does anyone know what Niessin, Steven Kretchmer and Gelin Abaci uses?

Is their exact alloy proprietary?

I have not found it revealed on their websites, only that it is 95% PT.

Special heat treatable spring alloys.
The exact mix is secret.
Big downside is that if they get to hot they lose their spring and have to be reheat treated. (repairs with a torch and sometimes over polishing can heat them to that point)

 

[bluemoi]

Thanks for the pics and images , I do love the platinum/iridium color. Very nice!

 

[Diamond Explorer]

Date: 5/24/2009 8:21:46 PM
Author: strmrdr

Date: 5/24/2009 5:41:59 PM

Author: Diamond Explorer






Storm,



What more can you tell me about Plat/Silver alloy. I would think the temperature of molten platinum would be too high to easily add silver. There would definitely have to be a special technique for alloying silver in platinum to avoid vaporizing the silver

http://www.abipreciousmetals.com/Sterling%20with%20Platinum/Sterling.htm


Plat-sterling is 95% silver 5% plat.

Out of all the ''white'' metals used in jewelery my favorite is silver.

Ah I see, Yes that is a good alloy. Plat-sterling. I am surprised more high end designers dont use it for their silver. Do you know if metal stock is widely available?

 

[John P]

Date: 5/24/2009 5:41:59 PM
Author: Diamond Explorer

John,

In that chart you posted do you know if the PT/IR blend is 90/10 or 95/5?

I suspect it''s 95/5 Jonathan. 90/10 would be about the same as Pt/Co.

 

[John P]

Date: 5/24/2009 8:24:45 PM
Author: strmrdr

Date: 5/24/2009 5:56:24 PM
Author: Moh 10
Which PT alloy is best for tension settings?

I believe you'd want an alloy that maintains its ability to grip, or resists bending open.


Does anyone know what Niessin, Steven Kretchmer and Gelin Abaci uses?

Is their exact alloy proprietary?

I have not found it revealed on their websites, only that it is 95% PT.

Special heat treatable spring alloys.
The exact mix is secret.
Big downside is that if they get to hot they lose their spring and have to be reheat treated. (repairs with a torch and sometimes over polishing can heat them to that point)

Right. In fact you can heat treat/age some specialty alloys all the way to HV200+, which is the same range as stainless steel and titanium jewelry. Nothing wrong with that but since they behave more like tool steel than precious metals you won't find them categorized with the common jewelry alloys.

 

[strmrdr]

Date: 5/25/2009 2:55:21 PM
Author: John Pollard


Right. In fact you can heat treat/age some specialty alloys all the way to HV200+, which is the same range as stainless steel and titanium jewelry. Nothing wrong with that but since they behave more like tool steel than precious metals you won't find them categorized with the common jewelry alloys.

yep
What I cant figure out is why more plain bands arent offered in alloys like plat/s+~1 or plat/s+~2 especially for men.

 

[bluemoi]

If a setting was made 950/IR and equates to 80 HV, I read that it can be work hardened to 140 HV. So in that respect wouldn''t the prongs and overall setting be less prone to bending/fatiguing in smaller sections or elements?