Scratch and dent resistance of white gold versus platinum
This past week a jeweler showed me a man’s platinum and diamond band
that had been so dented all around the edges that the customer asked
to have it redone in white gold. The jeweler had forewarned him that
white gold would be more resistant to scratches and dents based on
his experience with rings for other men who are hard on rings. I
asked the jeweler what platinum alloys his rings were made of and he
said 95 and 90% platinum and 5 or 10% iridium or ruthenium. I think
he got his rings from various manufacturers, but I neglected to ask
who made his rings and if they were cast, stamped or hand-fabricated.
Have any other jewelers on this forum had customers complain about
dented and scratched platinum rings? 2. What nickel-free white gold
alloys or platinum or palladium alloys would you recommend for men
who do hard manual labor rather than desk jobs? 3. Is there a large
difference in scratch and dent resistance between cast and stamped
(die-struck) rings?
Trouble is white gold isn’t white its slightly yellow so we have to
Rhodium plate it to make it white. Platinum is tougher and more
difficultto polish. Several of my customers got me to remake their
white gold ringsin Platinum because the Rhodium coating wears through
in about 6 months. Palladium is a good tough metal and is a true
white metal so doesn’t change colour as it is worn. I used to make
gents wedding rings out of Titanium, now that is tough and you can
inlay precious metals into it, it is also hypoallergenic like
Platinum. The best white gold is 18 ct with palladium as the alloy.
Nickel alloys are used less and less because of nickel allergyfears
but. Just remember there is no such thing as “White Gold” it always
occurs naturally yellow, we add white metals to whiten it but the
result is never completely white. As a white metal highly polished
Platinum takes a lot of beating. I have never found any difference
between cast and wrought Platinum in daily use. I certainly wouldn’t
recommend changing from Platinum to White gold. Hope this useful, I
look forward to seeing other people’s finding.
Renee- A platinum wedding band will out last a white gold wedding
band by at least two generations.
Platinum will scuff up, and dent. The prongs will spread, but the
metal does not wear away.
Gold will wear out. Platinum galls. In older traditional plat
jewelry the makers would often just put a soft satin finish on it
because that’s what it will look like in the long run of every day
wear.
When faced with a banged up platinum ring I just mostly burnish it
by smearing the metal back into place. You can reshape older plat
prongs that have spread as well. That’s why so many of the really
lovely old Edwardian looking delicate filagree diamond rings are
platinum. It can stand up to wear. The old die struck white gold
imitations of the same rings are pretty much worn out and have
multiple repairs on them.
Given a choice we like to use 10% Irridium plat because it’s old
school and that’s how we roll in our shop.
My experience is that Platinum is more wear resistance then gold by
about 3 times but it is also more mailable so it will bend earlier
then gold but has no memory so when you bend a prong it stays where
you put it. I never use white gold to mount stones. only platinum.
unless the design calls for yellow or green or rose.
So for a man platinum will show more scratches and dents then white
gold butwill wear out three times quicker then the platinum. Platinum
is about twice as dense as gold. Molecules packed twice as
close together. Thus the wear resistance.
White gold was developed as a substitute for platinum when it became
scarce due to its use in industry during WW1.
Platinum wears differently to gold or silver. When the omnipresent
microscopic abrasive dust that everybody comes into contact with all
day and every day scrapes gold or silver, it cuts a tiny sliver away
which is then lost. When it scrapes platinum it sort of ploughs it,
rather like when a farmer ploughs a field. The tiny scratches tend to
curl over themselves rather than being scraped out. Since the
scratches are in random directions, the result is that the surface
tends to be self-healing, and thus is far more resistant to wear that
either gold or silver.
I seem to recall that there is another, rather serious, objection to
white gold. I might be wrong (and no doubt somebody will shout if I
am), but white gold is not a true alloy; instead of being a frozen
mixture it’s a frozen emulsion because the constituent metals don’t
actually mix. Unfortunately, there is a very common substance that
can attack the molecular boundaries of that frozen emulsion, namely
salt, which results in cracks. Sea water contains salt. I’ve had to
repair lots of cracks in white gold, but the result is seldom
permanent; further cracks appear elsewhere.
Platinum is much more abrasion resistant than any white gold so
changing to white gold is probably not a great idea. Some high nickel
white golds are harder than most platinum alloys but, hardness is not
the same as abrasion resistance and quite a few folks get confused
about this. Hardness is resistance to denting it is measured by
trying to force a ball shaped or pointed pyramid shaped indenter or
brale into the sample being tested at a specified force and then
measuring the size of the dent. Scratch or abrasion resistance is not
so easily measured but is typically done with some form of abrasive
and a standardized application of rubbing that abrasive onto the test
surface. Many if not most platinum rings are soft but very wear
resistant so will last a lifetime or two. White gold will not exhibit
this same longevity.
Dear Hans Meevis, I was simply surprised that a jewelerwho
specializes in wedding rings has found that his customers are
betteroff buying white gold than platinum and says that it is easier
to replate white gold with rhodium than to fix dents and scratches
in platinum. I had never heard a comment like this before. In
general, jewelers have told me that the advantages of platinum (e.
g., hypoallergenic, not requiringplating, abrasion resistance)
surpass those of white gold. I agree with you that people should take
off their rings when doing hard work, gardening, or contact sports
and I always advise this. However, many people don’t want to take
their rings off for sentimental reasons orfor fear of losing them. I
tell them to at least select a low protectivesetting and to wear
gloves if possible. I also tell people that stamped rings generally
wear better than cast rings, but I have neverseen any data as to what
extent they wear better. Perhaps there was a casting problem with the
platinum rings the jeweler had sold. I do indicate advantages and
disadvantages of different platinum alloys based on from
the Platinum Guild and jewelers specializing in platinum, but there
is always something new to learn about possible alloys especially on
forums like Orchid. I suspect that this jeweler’s white gold rings
contain nickel, and I wondered what his experience would have been
over the years if his rings had been made of nickel-free white gold.
I think it is important to listen to people who sell a lot of
wedding rings and find solutions to the problems they encounter.
Thank-you Harnish for your comments and answers. Like you, I have
always thought that platinum and palladium are better choices for
wedding rings because of their natural gray color, which does not
require plating. However when a jeweler specializing in wedding
ringstells me that his white gold rings hold their polish better and
are significantly more resistant to denting and scratching, this
prompts me to get further and look for solutions;
especially when he says it is easier to replate rings than to fix
the scratches and dents on platinum. Other American jewelers have
told me that one of thebenefits of nickel white gold is that it is
more scratch resistant thanplatinum or palladium white gold.
According to Alan Revere’s “Professional Goldsmithing” book tables,
nickel white gold is harder and has a higher tensile strength than
palladium white gold. However, tables can sometimes be deceiving,
which is why I was interested to hear about the experiences of
jewelers on this forum. Perhaps people who are hard on jewelry should
get a brushed finish and sometype of engraved look on their platinum
so that scratches and dents are not noticeable.
I have used Palladium white gold quite a lot and indeed it is
probably the best of the white gold alloys, I have found it wonderful
for creating basket settings fabricated from 0.9 mm wire giving an
extremelyrigid structure and so easy to solder. I find it is still
slightly yellow particularly after being worn for a bit. It does
polish much easier than Platinum, I agree, but once you know the
procedure for polishing Platinumit isn’t a problem. They all dull
down in use, Platinum being a true white metal goes grey, white gold
alloys show a slight yellow tinge. Platinum claw tips I have found to
be much more durable than white gold but have to agree Palladium
white gold is also excellent. White gold is easier to deal with when
sizing, Platinum solders tend to show when polished but you can weld
it however very high temperatures are required. Fashion is forcing us
into creating white gold, good old yellow gold is much less
problematic, solders match the metal color better and are easy to
use, it polishes easier and as the polished surface dulls down it
still maintains it color. I guess the only true white metal is
silver, the Victorians used it in their stone setting and when it is
cleaned up and polished it really sparkles. Also it is wonderful for
carving and pave setting but the down side is it does tarnish and is
a bit soft. Still I can’t grumble cleaning, polishing and Rhodium
plating white gold rings is a nice little earner in our business.
People tend to have it done every six months and the rings look
likenew again, cheaper than putting the car through the car wash
every week and we can report on the condition of the settings.
As you pointed out It is very important to differentiate between
platinum alloys when judging resistance to scratching and denting. It
sounds like this customer actually deformed the ring, which would
indicate extremely hard wear OR a very soft alloy. I have seen it
happen in both cases. If the alloy was 950PtRu or 950 PtCo, those
would represent the typical medium hardness ranges that we see in
high purity platinum alloys coming it at around 130 Hv depending upon
the quality of the casting and the load used in the Vickers micro
hardness testing. These are mainstream alloys and we know that the
hardness is decent, although design will play a role too when it
comes to features that might easily distort. If his ring was cast in
950 PtIr I would expect it to become highly distorted since this
alloy is far too soft to be used in jewelry castings, coming in at a
dismal 80 Hv.
There are harder alloys on the market that can be used for customers
that tend to be hard on their jewelry. For such people we cast
Hoover’s 950 Pt HCA (hard casting alloy) that contains gallium and is
significantly harder than the mainstream alloys at 180Hv in the
as-cast state. A platinum men’s band that is cast in this alloy while
also incorporating a smart design with respect to wear features
should please even the hard-wearing consumer. And the previous
comment was correct, you can be unhappy with wear in white gold just
as easily as you can with platinum if the true expectations of the
consumer are not identified OR if the wrong alloy is used for the
job.
Nickel white gold is whiter, but has problems with cracking and
allergic reactions. It also is not fully white, so rhodium plating is
often used resulting in a disappointed consumer when it starts to
wear off. Pd white gold is yellower and softer. If the consumer likes
the color without rhodium, this one is a pretty good choice but
remember it will never outlast the same piece cast in Pt.
When it comes to cast platinum your best bet is to aim for at least
a 130Hv range. Pt900Ir, while it is a lovely alloy for melting and
fabricating, is borderline soft at 110Hv. You can overcome part of
this with a sturdy design and thicker prongs, etc., but wear will be
more apparent over time than with the 130 range. We cast a lot of it
here for our customers, but the majority of these jewelers are
cognizant that they need to design according to its structural needs
for best success.
Lastly, you will see a big difference in hardness between cast and
die-struck pieces. The die striking process will work harden metal
to very impressive ranges. Having said that, this hardness hike is
temporary insofar and the minute you anneal during manufacture or
repair, you will revert back to the annealed hardness which is
comparable with the as-cast hardness.
Platinum is about twice as dense as gold. Molecules packed twice as
close together. Thus the wear resistance.
Fine gold and platinum are almost the same density as is lead. It is
not the density that determines wear resistance. Titanium is a very
wear resistant metal and is not very dense at all.
I seem to recall that there is another, rather serious, objection
to white gold. I might be wrong (and no doubt somebody will shout
if I am), but white gold is not a true alloy; instead of being a
frozen mixture it's a frozen emulsion because the constituent
metals don't actually mix. Unfortunately, there is a very common
substance that can attack the molecular boundaries of that frozen
emulsion, namely salt, which results in cracks. Sea water contains
salt. I've had to repair lots of cracks in white gold, but the
result is seldom permanent; further cracks appear elsewhere.
Well it is a true alloy but it is not a single phase alloy. Nickel
and gold will not form a continuous series of solid solutions at
room temperature. They will in fact form two different crystal
structures in the alloy, a gold rich phase and a nickel rich phase.
This is one of the reasons the nickel white golds are so hard. The
presence of two distinct crystal structures makes it harder for the
matrix to deform and this makes it hard. The nickel rich areas of
the alloy are susceptible to chloride stress corrosion cracking. To
get this type of cracking the metal has to be under stress and
exposed to a chlorine rich solution. Because prongs or bezels are
under stress from the bending of the metal during setting they are
the parts that typically crack due to this problem. Swimming pools,
hot tubs etc that have chlorine in them or the ocean provide the
chlorine solution and then you have all the necessary conditions.
This is why nickel white gold heads or settings are not such a good
idea.
The nickel rich areas of the alloy are susceptible to chloride
stress corrosion cracking. To get this type of cracking the metal
has to be under stress and exposed to a chlorine rich solution.
Because prongs or bezels are under stress from the bending of the
metal during setting they are the parts that typically crack due to
this problem. Swimming pools, hot tubs etc that have chlorine in
them or the ocean provide the chlorine solution and then you have
all the necessary conditions.
This is why nickel white gold heads or settings are not such a
good idea.
Thanks for correction James; I was nearly right. Does that mean that
palladium white gold doesn’t have the same problem?
As it happens, I’ve experienced cracking on ring shanks that you
wouldn’t think had experienced stress.
Fine gold and platinum are almost the same density as is lead. It
is not the density that determines wear resistance. Titanium is a
very wear resistant metal and is not very dense at all.
Density of pure platinum is 21.4, 950 platinum is 20.1
" " " gold 19.3, 18ct is 15-17
" " " lead 11.3
" " " silver 10.5
" " " titanium 4.5
Which means that (pure) platinum and gold are almost twice as dense
as lead.
my experience has been that the stones I have set in platinum need
retippingAbout every 12-20 years as opposed to 5-10 years for the
same rings withgold prongs of any color. Thus my statement it is
twice as resistant to wear as gold…
I may be wrong about the molecules but not wrong about the memory or
wear resistant. And by volume when I buy platinum it is heavier then
alloyed gold. might be due to the fact it is a higher percentage of
pure metal then 14-18kgold. But when I order platinum casting grain I
get about half the volume as I get with gold. 24k gold wears faster
then platinum.
Have to admit that I have never bothered to take the time to break
it down into the percentage of alloy vs pure metal. Thanks for
pointing this out. I stand to be corrected. Thanks. I have great
respect for your info and formal education which you share with us
all freely and respectfully.
Thanks for all you do to help each one of us advance in our
knowledge of ourfield.
my experience has been that the stones I have set in platinum need
retippingAbout every 12-20 years as opposed to 5-10 years for the
same rings withgold prongs of any color. Thus my statement it is
twice as resistant to wear as gold..
That fits with my experience and what others have related to me.
I may be wrong about the molecules but not wrong about the memory
or wear resistant.
Yes you are right about that.
And by volume when I buy platinum it is heavier then alloyed gold.
might be due to the fact it is a higher percentage of pure metal
then 14-18kgold. But when I order platinum casting grain I get
about half the volume as I get with gold. 24k gold wears faster
then platinum.
Yes if you had said 18k or 14k I would not have said anything. It is
that the pure metals are very close to each other in density. And I
was not thinking clearly when I threw in lead as an example.
Thank-you for all your helpful comments regarding platinum versus
white gold. I’ve summarized them in the following list entitled:
Platinumring selection tips for people who are hard on rings and
don’t want to take them off
For casting, select a platinum alloy with at least a 130 HV range
such as 950PtRu or 950PtCo, Better yet, select an alloy that
contains gallium such as Hoover’s 950Pt HCA (hard casting alloy) at
180 HV. Avoid 950PtIr, which is far too soft for casting at 80 HV.
Pt900IR is borderline soft at 110HV. (from Teresa Frye techformcasting.com) 2. Consider selecting a platinum ring with a
soft satin finish because that is what it will look like in the long
run of everyday wear. (FromJo Haemer).
Select a sturdier design and thicker-than-average prongs. Design
according to the structural needs. (Teresa Frye). 4. Consider buying
a die-struck ring if no sizing or work is requiredon it. According
to Teresa, you will see a big difference in hardness between the
cast and die-struck process as long as the die-struck ring is not
annealed.
In general, everyone seems to agree that platinum shanks and prongs
are much more wear resistant than those of white gold. Jo estimates
by at least two generations. Vernon and James say two or three times
as resistant. In addition, platinum doesn’t have problems with
cracking like white gold.
I will relay this to the wedding ring specialist who has
received many complaints about platinum susceptibility to denting
and scratching and who therefore usually recommends white gold. He
could probably reduce the number of complaints by not using castings
of Pt5Ir and Pt10Ir for everyday rings.
Many thanks for all of your excellent posts. Besides providing new
they also help reinforce whatwe already know.
Renee Newman
P. S. If I misinterpreted anything of what you said, please let me know.
Renee- You do not need heavier prongs in platinum. The beauty of
Platinum is that you can make things much lighter than in gold.
Especially when fabricating which really is the old school preferred
method of working in Platinum. Oh yeah, I’m gonna get heck for that
last statement:-) Have fun and make lots of jewelry.