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Chlorine and yellow gold


#1

I’ve just seen my second ring–one that I made and one made by
someone else-- fail do, I think, to chlorine… Very different rings,
both in 14k yellow. Fractures and cracks–too many to repair and in
inconsistent places. It all looked like it was somehow chemically
altered.

I finally asked both clients if they swam. Both did-- every day. In
chlorinated pools.

I’m telling white and yellow gold owners to not swim in their rings,
etc.

I’ve heard a lot about nickel white golds and chlorine, but can’t
recall seeing much about yellow.

Anyone know the mechanism?

Thanks,
Andy


#2

Andy the chlorine and copper in yellow golds react, much like adding
an intentional patina. I can’t reacll what the exact chemical
compound formed is ( I believe it is a perchlorate) taht will in
small amounts start to turn yellow golds between 14 and 22 kt yellow
-green initially, but repeated exposure is like dipping it in the
solution daily… one remedy ( not so desireable) is a sealant that
could be an option at the counter for swimmers that don’t wish to
remove their jewlery frequently… much like having an eyeglasses
lens coated - it could be offered as an extra add-on to the final
cost of a one off piece. Adding a bit of germanium and bismuth to the
alloy can assist in delaying the reaction and formation of cupric
oxides and copper chlorates that will form in chlorinated water. One
recommendation that you could make to your customers is to opt for
enzymatic additives instead of chlorinating their pools or spas.
THey seem to be eqaully effective as far as algicidal and
bacteriaocidal properties but the change requires a major effort and
perhaps draining the respective tank, neutralizing and cleaning, and
starting over with a fill.

I have for years, given my clients a neutralizing solution to use
after each exposure to chlorinated water ( if a client tells me they
are going on a trip I always give them a bottle of solution to take
as hotel pools are the most overchlorinated bodies of water I know
of, and will turn gold and silver black often in one dip, shower or
swim), and a recepit to make their own when they run out. It is
merely a bit of good customer service: I consider it part of
educating those interested in having a bit of background on their
jewelry and care instructions . I haven’t ever had anyone complain
about the affects of chlorinated,sulfur, or other mineralized waters
on their jewelry-after explaining the effects of chemicals and the
sources-in cosmetics,synthetic parfums, and other hazards and
offering a sealant as a preventative ( though I do so with a caveat
of reapplication becoming necessary down the line with most sealant
products or marine varnish being used to seal the surfaces that are
sealable… waxes are solved out in some heavily chlorinated pools and
upon exposure to atomized eau’d’colognes and lesser alcohol
containing products).

R.E.Rourke
feel free to contact me off list to clarify anything you desire


#3

Gold and chlorine form gold chloride, especially in the presence of
iron and/or certain organic acids (i.e. palm sweat). Gold chloride
is the royal blue color we see in stained glass from the medieval
period.

I was educated on this particular subject when, as a very young and
inexperienced mining engineer, I found a very nice mass of gold
wires and crystals near breckenridge colorado. the mass was
surrounded by limonite, with gold wires and octahedrons poking out of
the crud. I tried to clean it by soaking in Hydrochloric acid
overnight. in the morning i poured off alot of a strange purple
colored liquid, only to find no gold left at all, just alot of
crumbly limonite.

the one that got away.

Mark Zirinsky
denver


#4

Hello Andy,

I used to live in the pool all summer (when I was younger and
unaware of sun damage!), and wore my rings and neck chains all the
time. I’m one of those who will wear jewelry for weeks at a time.
Anyway, other than having a ring sizing solder joint fail, I can’t
recall any other problems. Can you add some details about the problem
rings, specifically:

A. Were the pieces cast or constructed from sheet & wire?

B. Were they two-tone gold?

C. You mention that the cracks are in inconsistent places - is there
any commonality so far as skin contact or is the damage scattered on
all surfaces?

D. You said they wore the rings in the pool. Is the pool a spa/hot
tub or an unheated swimming pool or both?

As an aside, it would be useful to know more about the pool’s water
chemistry, but most folks aren’t aware of anything about pools other
than that the water is chlorinated. There are many other chemicals
that are used to alter alkalinity, pH, and help the filters function.
Hot tubs/spas create a whole other set of conditions due to the
combination of higher temperatures and different disinfectant use.

This is an interesting problem, and I’m curious to find out more.
Judy in Kansas, who is gearing up for a weekend show.


#5

Andy-

Even pure gold is subject to attack when an abundance of chlorine
ions is present in solution. The mechanism is a complex of one Au
ion and four (as I recall) Cl- ions. That is why gold is present in
sea water. I suspect that stressed areas and grain boundaries pesent
in 14K gold would be more susceptible to this kind of corrosion.

Some of the chemists out there might be able to shed more light on
the subject.

Richard Davies


#6

Thanks, RE. The neutralizing solution sounds interesting. Care to
share the formula?

I’m not sure how I feel about using coatings in my work. I still
think that I’ll urge removal.

As you said, it’s the public spas and pools that are the problem.

Thanks,
Andy


#7

Andy,

Any signs of mercury? The symptoms sound the same although gross
contact with metallic mercury usually are obvious.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing


#8
Some of the chemists out there might be able to shed more light on
the subject. 

I’m not a chemist, I just play one on TV. There are two things that
will dissolve gold, at least in the real world (a nuclear reactor can
do it too, but that’s different) - cyanide and chlorine. One of the
few stable gold compounds is gold chloride, and it’s not that stable.
Aqua Regia in general terms has chlorine ions, which is what dissolve
the gold. Note that the reaction inside the acid mix is way more
complicated than just having Cl- ions floating around, but in the end
there is reactive chlorine available. Somewhere I read the actual
reaction - I don’t recall, but there are like 5 steps of reaction in
Aqua Regia. One time we got a ring that had been lost in a sink and
discovered in the trap some 5 years later, and it was a rotten shell
of a ring, from using chlorinated cleansers in the sink. Now, the
chlorine in a swimming pool is a fairly tiny amount by comparison,
and just swimming now and again won’t hurt quality gold jewelry, but
then again chlorine will attack just about everything on earth in
some way or another. Maybe an olympic swimmer really shouldn’t wear
gold, but lounging by the pool for an afternoon probably won’t do
much if anything.

http://www.donivanandmaggiora.com


#9

Hi Andy,

I have been a lap swimmer for about 40+/- yrs. (1/4 -1/2 mile ; 3-5
times /week) I have always worn my jewelry : 14K, 18K, Yellow & white
Never had a problem

Linda


#10

I have never heard that chlorine was selective and only attacked
white. Since it seems to attack first on the places the metal is
bent, that is the prongs, it may seem that it is only going for the
white.

From the breaks I’ve seen over the last 30 years since chlorine
damage to gold first became known, I have a speculation as to what
is happening: I think the chlorine is attacking the surface of the
alloy metal grains and forming either copper chloride or nickel
chloride. Remember that the strength of the metal comes from the way
the alloy grains and the gold grains are locked together.? When the
chlorine hits the gold grain, it doesn’t penetrate or react with
it.? When it contacts the alloy, it is easily possible to form a
chloride compound.? The compound is no longer locked to the gold
grain next to it.? In effect, the glue holding the grains together
has been removed.? Result - the grains fall apart.? When I see
angular grain on a new break, I immediately suspect chlorine damage.

My expectation is that the electrons in the metal bonding of the
grains are inclined to stay within the grain.? That is, the grains
are discrete and there are not compounds of gold/nickel or
gold/copper at the boundaries.?? In effect, the surface of each
alloy grain is a sea of electrons ready to bond.? Inside the grain,
the electrons share among the atoms so they are not as available as
they are at the grain surface.? (If I am correct, a similar
one-molecule-thick layer of chloride is probably created if pure
copper or nickel is exposed to chlorine.)

Is there a metallurgist who can tell if my speculations make any
sense?

Peace,
Francis


#11

Gold chloride From Wikipedia:

Gold(III) chloride, traditionally called auric chloride, is one of
the most common compounds of gold. It has the formula AuCl3. The
Roman numerals in the name indicate that the gold has an oxidation
state of +3, which is the most stable form for gold in its
compounds. Gold also forms another chloride, gold(I) chloride
(AuCl), which is less stable than AuCl3. Also, chlorauric acid
(HAuCl4), the product formed when gold dissolves in aqua regia, is
sometimes referred to rather loosely as “gold chloride”, “acid gold
trichloride” or even “gold(III) chloride trihydrate”.

Gold(III) chloride is very hygroscopic and highly soluble in water
and ethanol. It decomposes above 160 C or in light, and it forms a
variety of complexes with many ligands.

Structure

AuCl3 exists as a dimer both as a solid and as a vapour; the bromide
AuBr3 follows the same pattern. Each Au center is square planar.
This structure is reminiscent of the bitetrahedral structures
adopted by AlCl3 and FeCl3. The bonding in AuCl3 is mainly covalent,
reflecting the high oxidation state and relatively high
electronegativity (for a metal) of gold.

Chemical properties

Anhydrous AuCl3 begins to decompose to AuCl at around 160 C;
however, this will in turn undergo disproportionation at higher
temperatures to give gold metal and AuCl3.

AuCl3 -> AuCl + Cl2 (>160 C)

3 AuCl -> AuCl3 + 2 Au (>420 C)

AuCl3 is a Lewis acid which readily forms complexes. For example
with hydrochloric acid, chlorauric acid (HAuCl4) is formed:

HCl(aq) + AuCl3(aq) -> H+AuCl4-(aq)

Ionic chlorides such as KCl will also form the AuCl4- ion with
AuCl3.

Aqueous solutions of AuCl3 react with alkalis such as sodium
hydroxide to form a precipitate of impure Au(OH)3, which will
dissolve in excess NaOH to form sodium aurate (NaAuO2). If gently
heated, Au(OH)3 decomposes to gold(III) oxide (Au2O3) and then to
gold metal.

Preparation

Gold(III) chloride is most often prepared by direct chlorination of
the metal at high temperatures:

2 Au + 3 Cl2 -> 2 AuCl3

Uses

Gold(III) chloride is one of the most common gold compounds and it
is therefore used as the starting point for the synthesis of many
other gold compounds, for example the water-soluble cyanide complex
KAu(CN)4:

AuCl3 + 4 KCN -> KAu(CN)4 + 3 KCl

Gold(III) salts, especially NaAuCl4 (made from AuCl3 + NaCl),
provide a non-toxic alternative to mercury(II) salts as catalysts
for alkyne reactions. One important reaction of this sort is the
hydration of terminal alkynes to produce methyl ketones.

Ketones are generally formed in over 90% yield under these
conditions. Also useful is the related amination of alkynes which
can use gold(III) catalysis.

In recent years AuCl3 has begun to attract the interest of organic
chemists as a mild acid catalyst for other reactions such as
alkylation of aromatics and a conversion of furans to phenols (see
below). Such reactions find use in organic synthesis and in the
pharmaceutical industry. For example, 2-methylfuran (sylvan)
undergoes smooth alkylation by methyl vinyl ketone at the 5-position.

The reaction gives a 91% yield in only 40 minutes at room
temperature, using only 1 mole% of AuCl3 in acetonitrile. This yield
is noteworthy since both the furan and the ketone are normally very
sensitive to side-reactions such as polymerisation under acidic
conditions. In some cases where alkynes are present, a phenol may be
formed

The reaction undergoes a complex rearrangement that leads to
formation of the new aromatic ring

Precautions

Gold(III) chloride should be handled wearing gloves and goggles;
direct contact with the material should be avoided.


#12

This sounds reminiscent of twp possible conditions. The first obvious
one is mercury which might not - of course, be as noticeable on white
gold as on yellow gold. The action of the mercury is to dissolve the
gold and, if there is enough mercury present, turn it to slush.
Contact with just a tiny drop of mercury is enough to ruin any gold
ring. The other possibility is a condition I often find in old clocks
and what is known here as ‘brass disease’ or ‘brass embrittlement’.
The brass just crumbles away to dust over a period of time and the
condition is thought to be caused by ammonia. Ammonia and ammoniated
cleaners were commonly used in cleaning clocks during the 20th
century and, whilst no immediate effects were seen, the long term
effects on the cast brass could be devastating. As far as we can
tell, the mechanism of this destruction is purely mechanical and
worst affects parts which have been cast and then subsequently
hammered to harden them (and thus harden the grains of the cast
metal structure). The ammonia, either as a liquid or gas, gets in
between the plates or grains of the casting’s crystal structure and
lodges deep within the structure. Any water evaporates but the
ammonia gas remains trapped in the deepest crevices. It may also form
complex compounds with the alloying metals but I don’t think this has
been proved one way of the other yet. When the metal next gets wet,
the ammonia gas which is very hygroscopic and/or the compounds
formed, absorbs the water molecules and expands, forcing the grains
of the casting apart and creating bigger fissures into which more
ammonia can diffuse. Over a period of time this cycle of wetting,
expansion, and drying can force the crystal structure apart enough so
that the crystals no longer interlock mechanically and so the metal
turns to dust. All this is, of course, happening at the molecular
level but the effect is that the brass or other metal crumbles away
and cracks develop which eventually go right through the metal
causing lumps to drop out. So, if this is happening in your case, it
might not be the swimming that is the cause but maybe the owners use
household cleaners which contain ammonia or come into contact with
urine (as in babies or animals) on a regular basis?

Best wishes,
Ian
Ian W. Wright
Sheffield UK


#13

well Andy I agree about coatings= unless the client insisted (or
wanted something made of brass or copper and it was worn against the
skin) I urged against it as they always need removal and
reapplication at some point down the road- which, while bringing
them back- isn’t the reason I want them to return…

As for the solution I gave to athletes and swimmers : the beauty of
getting them to use it is is mostly packaging… I used great emerald
green bottles from Berlin Packaging, and the soloution was: 6 parts
carbonated water to 2 part vitamin C liquid 1 part sodium
bicarbonate and 1 part calcium carbonate (eggshell source, or USP),
agitated or shaken. and into that 1 gallon I add1 &1/2 oz
glycerine-vegetable source, and 1/4 oz. Labdanum and about 1 tsp. of
amber crystals, or an ounce of bisabolene and a half ounce of
mandarine absolute (although any essential oil, N. I. oil or alcohol,
ketone or terpene can be used to impart a scent if desired…-and on
what season it is and if its for men or women the colourant is
unnecessary as the green bottle protects the solution from light and
doesn’t need coloring- though you could use anything you like in any
colour you want. (though i try to go for androgynous scents so I
don’t have more solutions lying around than i do on a given day - at
present i probably have 30 different preparations stored for
everything from stripping solutions, pickles, & mordants to fixatives
and colourants…Presentation is important to me in what I give a
customer or client…

If you, or anyone is interested in making your own formulations I
highly recommend the perfumer’s workbook as a testing ground to make
certain you are using ingredients and chemicals that won’t react
with each other or skin, or metals…It’s free and a wealth of
and…if you are a collector of substances like I am, it’s
a quite valuable refernce work that you can add your own 1500
ingredients or substances to and from there formulate away!

R. E. Rourke


#14

John,

While you are correct in saying that the chlorine in most swimming
pools will take quite a while to damage the gold in a ring, it won’t
take nearly as long to eat up the solder in that head. Commercial
swimming pool filters have proven to be great “diamond mines”. Also,
in places in the country where hot tubs are a way of life,
especially over-chlorinated ones, I’ve had customers come back with
brown-stained gold jewelry after ONE immersion, especially chains.

Bromine and a few other compounds will have the same effect on gold
as chlorine, but we don’t run ntothem much.

Wayne Emery


#15

Duh…Helen…what does all that mean in layman’s terms?

Cheers from Don in SOFL


#16

Andy,

I remember seeing a technical article from Hoover and Strong about
gold and chlorine/bromine… a quick search found it at:
http://www.hooverandstrong.com/pdfs/11Cat06Tech-Links.pdf (the
bookmark is “Do Chemicals Affect Your Gold?”

They did a comparison study based on concentration of chlorine and
bromine vs temperature. The results (complete with pictures) are
quite interesting and may answer some of your questions. They may
also answer why some folks have written in that their daily exposure
has not had an adverse effect to their jewelry, as temperature does
seem to be a factor.

Hope this helps!

Karen Goeller
No Limitations Designs
Hand-made, one-of-a-kind jewelry


#17

John,et al,

We are not really talking about lounging by the pool. The two cases
that have caught my attention were both involved with daily swimming
in public pools. One is a friend whose ring I made and which was fine
for 7 years. She was advised by a doctor to swim every day for a
period of months. This was in the late spring. Trouble followed
immediately.

The other client brought me a ring that I had added a side ring to
many years ago. I fabricated the sapphire and diamond side ring that
was then added to a channel set band made by someone else. The rings
were attached via cross straps/braces so that a single guard ring was
created between which slid a third ring.

The channel set ring had broken. Upon louping I found other cracks
beginning and then looked at my ring. Seams between basket prong
heads were pitted and what really surprised me was that a prong was
broken clean through below the stone between the bearing ring and the
lowest ring of the head. I have read that when bricks break in an
earthquake rather than fail along mortar joints the earthquake is
quite profound. It is this breaking in a solid area on the ring that
really made me shake my head. Other cracks were also developing
elsewhere.

A light went off and I asked if the client swam. She was surprised
and said that yes, she was an avid swimmer and swam daily in public
pools.

I don’t believe that casual immersion in a public pool will ruin
gold jewelry-- quality or otherwise. But what is “casual”? How many
times a month should we tell clients is safe? Better, I think, to
remind them of the danger and let them act accordingly.

Andy


#18

This is a difficult one as any jewellery we wear constantly usually
has some emotional attachment with it, like a wedding ring set. Most
people don’t usually like removing them, particularly the plain gold
band. But this is obviously a significant problem for regular
swimmers or people coming into contact with chlorine based products
on a regular basis.

Removing jewellery before going to the public swimming baths and
leaving it safe at home is probably good practice, as most of us
probably would not be keen on the idea of leaving such valuables
unattended with our clothing whilst we swim, even in a locked
locker.

It’s a judgement thing - we may have a huge emotional attachment to
our gold jewellery that we like to wear permanently, but if we swim
on a regular basis, then there’s a real danger that there will be
nothing left to attach any emotion to. As Andy says it’s best to
advise customers of the risks and let them make the choice as to
whether to wear or not to wear.

Helen
UK


#19

Andy,

What you are describing has all the hallmarks of stress crack
corrosion. It is most often found in nickel white gold but can also
show up in yellow as well. Read this article for the basics on the
problem

Jim

James Binnion
@James_Binnion
James Binnion Metal Arts


360-756-6550


#20

Here on the OBX of NC, we have interesting problems with gold
jewelry in hot tubs, pools and the ocean. They get eaten up. The
bromine used in most pools and hot tubs here combined with the heat
seems to do a great job of ruining gold jewelry. Housekeepers,
bartenders and mates on charter fishing boats around here seem to
use a lot of chlorine bleach for cleaning, and that seems to really
do the damage also. When I make wedding bands, particularly for the
local folks who do this work I make sure they know not to wear their
jewelry while immersing their hands in these chemicals.

Peggy on the OBX