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Verdigris, Poisonous copper compounds


#1

Was: Soldering outside

Keith, you’ll probably see this message a few days late, as orchid
seems to hate my posts! As we’re talking about the wikipedia page for
verdigris, you might have read further, to the part that says “As
verdigris consists of various poisonous copper compounds, one should
always wash one’s hands after handling”.We shouldn’t make light of
these kind of issues. I know that Leonid can seem like he’s just
being difficult sometimes, but this time, he really means it :wink: On a
more technical note, does anyone know if there is a particular % of
copper in gold and silver alloys that will cause verdigris to form?

Jamie Hall


#2

Greetings Microbiologist: You have convinced me that verdigris is
nasty stuff. Is it safe for the wearer to put a green patina on
bronze, brass or shibuichi? Is it safe if the patina is covered with
lacquer or varnish? I’ve seen beautiful green and blue patinas on
jewelry, but are the jewelers promoting a dangerous product?

Sally Parker


Ring turns finger green
#3

I used to carry a line of bracelets that were copper, brass etc…

They had been coated with a finish, probably lacquer, to keep the
bracelet from turning colors and to protect the wearer.

I THINK this was the company:
http://www.ganoksin.com/gnkurl/15a

Regardless, they have some info about copper worn as jewelry on
their site…

Keith Hible
madjeweler.smugmug.com


#4
I know that Leonid can seem like he's just being difficult
sometimes, but this time, he really means it ;) On a more technical
note, does anyone know if there is a particular % of copper in gold
and silver alloys that will cause verdigris to form? 

Yes verdigris (copper acetate) is poisonous as are most copper salts
but, you need to ingest a fair amount to cause problems. The LD 50
is 710 mg per kg in rats, this means that you need 7/10 of a gram
per kilogram of body mass to be lethal in 50% of the individual rats
dosed with it. That is a fairly substantial amount of copper
acetate. I am not advocating ingesting any of it but lets have a bit
of a reality check here you are talking about needing to ingest a
fair amount of the powder to get any kind of toxic effect.

To get any to form on gold or silver alloys would need lots of
copper, like more than 50% Cu in the alloy.

James Binnion
James Binnion Metal Arts


#5

Sally, I can’t answer your question with facts, just a little common
sense. The main thing is that it not be touching skin. If it were a
pendant, say, I’d solder a very thin sterling backing or clean the
back very well and use a sealant of some kind: epoxy, etc. Verdigris
will flake away, so if it were a big piece I myself would wax it
with a carnauba wax like Renaissance Wax which ought to prevent that.
Anything else would probably make it shiny and maybe spoil the
effect. Anyone else have ideas?

Gary S


#6
Yes verdigris (copper acetate) is poisonous as are most copper
salts but, you need to ingest a fair amount to cause problems. The
LD 50 is 710 mg per kg in rats, this means that you need 7/10 of a
gram per kilogram of body mass to be lethal in 50% of the
individual rats dosed with it. 

This is a common argument used to justify use of dangerous
chemicals. However, one must understand what does it mean for a dose
to be lethal. In all such testing timespan used is very short. Long
term effects is quite another matter.

Here is an interesting article on the Web about LD50 and similar
testing methodologies

Leonid Surpin
studioarete.com


#7
This is a common argument used to justify use of dangerous
chemicals. However, one must understand what does it mean for a
dose to be lethal. In all such testing timespan used is very short.
Long term effects is quite another matter. 

Im not trying to justify anything, it is a toxic chemical as I stated
in my post. You seem to be trying to justify your unsupported
assertions of the dangers of wearing copper jewelry with fear
mongering about verdigris which is a minute portion of the compounds
that copper forms when in contact with the skin.

James Binnion
James Binnion Metal Arts


#8

I thought my copper cuff was helping w/ my elbow tendonitis… are
you saying I shouldn’t be wearing it? (I’ve missed the beginnings of
this post.)

Trish


#9
I thought my copper cuff was helping w/ my elbow tendonitis... are
you saying I shouldn't be wearing it? (I've missed the beginnings
of this post.) 

Trish, wear your bracelet proudly. Whether copper bracelets have any
real affect on arthritis.is where the jury is out. I gather that
some in medicine think it really might, but that’s neither here nor
there. Copper is a necessary trace element in the human body, but
like most trace elements too much is not better. And though Jim B.
is correct in everything he says here, I would choose the word
"toxic" over poisonous, though both are true. Poisonous conjures up
images of sudden, instant death - curare and the like. If you ingest
almost any copper compound in serious quantities it will be very,
very bad. And copper acetate is one of the worst - copper sulfate
(the blue stuff) is another. DON’T EAT IT! That’s all, but I
wouldn’t be putting out green copper jewelry that touches the skin,
either. Copper is excreted slowly, like most metals. That means that
if you have a steady supply of it entering the body, it will build
up, little by little.

But that’s where the word toxic is better - that sort of build up is
bad for you, but you’re not going to keel over all of a sudden
either. Personally, I think copper jewelry that touches the skin is
something that shouldn’t be made in any quantity, for reasons of
public health. You’ll notice that it’s not made much except for
starving amateurs. If you can taste copper or metal in your mouth,
you have too much, however it came to be.

Get away from it for awhile, whether it’s wearing it or working it.
And don’t eat the green stuff or the blue stuff, like you (guys)
should need that explained. But it’s not cyanide either.


#10
I thought my copper cuff was helping w/ my elbow tendonitis... are
you saying I shouldn't be wearing it? (I've missed the beginnings
of this post.) 

I just happen to be reading The Believing Brain by Michael Shermer,
“How we construct beliefs and reinforce them as truths”

One of my favorite words is anecdotal. Often used with the word
evidence. Let’s see…anecdotal evidence…

Wikipedia: Anecdotal evidence is unreliable evidence based on
personal experience that has not been empirically tested, and which
is often used in an argument as if it had been scientifically or
statistically proven…

So I think anecdotal evidence is an oxymoron.

If evidence is based on fact, anecdotal evidence is rumor and/or
superstition.

Richard Hart G.G.
Denver, Co.


#11
I thought my copper cuff was helping w/ my elbow tendonitis... are
you saying I shouldn't be wearing it? (I've missed the beginnings
of this post.) 

The practice of wearing copper jewellery probably originated because
people believe that skin contact is beneficial due to copper
absorption. It may be true in the beginning, but once copper starts
reacting with elements, copper salts are formed, and instead of
copper, one gets steady stream of toxins.

Copper salts are toxic, and depending on individual can be toxic in
surprisingly small amounts. The most remarkable thing in this
discussion is that proponents of the idea that copper salts is
something not to worry about, basing their arguments on Government
published test results, particularly LD50.

Judging toxicity for humans on the basis of LD50 is like deciding on
safety of jumping from window, depending on how safe it would be for
a cat. LD50 is determined using rats. Average rat will thrive in
conditions, where human will perish within hours. Rats live in
sewers. It is their natural habitat. One should ponder on what rat
gets exposed to, in modern sewer, without any harm to itself. And
that is the animal that Government using for testing to determine
toxicity to average human. If there is a prize for the most
ridiculous idea ever, this definitely deserves it.

Leonid Surpin
www.studioarete.com


#12

I thought there was a whole big market for copper jewelry,
specifically as a health thing! That you should have copper touching
your skin… What was that all about?

Janet in Jerusalem


#13
the dangers of wearing copper jewelry with fear mongering about
verdigris which is a minute portion of the compounds that copper
forms when in contact with the skin. 

Quoting Jim for no particular reason, and I guess I could go back
and read all of this thread, but I haven’t. There’s a fundamental
thing that’s good to understand here, relating to chemistry and the
body and metals. No, I’m not a real chemist and I’m no doctor, but
this is simple stuff.

In order for something to impact your body ~chemically~ it must be
soluble, and preferably water soluble. You can eat sand and it won’t
(chemically) hurt you because it’s not soluble and there’s nothing
in your body that can dissolve it. That would require HF and there’s
none of that in your body.

The traditional precious metals - silver, gold and platinum - also
are not affected by your body chemistry, at least generally
speaking… Silver can be more marginal, but if you eat fine gold it
will just go through you - there’s nothing in your body that can
touch it. Not only that, but there are relatively few soluble
compounds of those metals in life - silver nitrate is one of the
few, and most people never encounter that.

On the other hand, copper is quite reactive, and most of it’s
compounds are not just soluble in water but very much so. When you
wear a copper ring and it turns your finger green, that is from
chemical reactions between your body chemistry and probably the
atmosphere. Wearing copper is just not the same as wearing gold, and
you need to understand that as a jewelry maker. The good thing is
that it’s also not especially toxic in the amounts most people here
will be talking about. Having a green finger is not adeath sentence.
Then again, if you’re making some bracelet that’s heavily encrusted
with green patina that can flake off or create dust, you’re not doing
your public any favors, either.

Just be aware - it’s not gold, it’s not the same as gold, and copper
compounds don’t belong in the human body in any sort of quantity.
Most of the toxicity issues come from mining and smithing, not
wearing a copper bracelet.


#14

Hi,

I thought my copper cuff was helping w/ my elbow tendonitis... are
you saying I shouldn't be wearing it? (I've missed the beginnings
of this post.) 

People have been using copper for about 10,000 years, so chances are
that copper jewellery is pretty close to that vintage.

Wearing copper isn’t a big deal, there’s no scientific evidence that
wearing copper close to the skin is beneficial, or detrimental
either.

Copper will enter you body through skin contact, usually due to
acids and sweat from the skin, but not in quantities that will kill
you.

Copper in trace amounts is essential for us to metabolise iron,
10,000 micrograms is the daily requirement.

Regards Charles A.


#15
I thought there was a whole big market for copper jewelry,
specifically as a health thing! That you should have copper
touching your skin... What was that all about? 

I still see them for same in chemist shops to relieve arthritis.

Scientifically it can only be proven as a placebo effect, sort of
like those power bands that were the rage, here in Oz, last year.

It’s marketing.

Regards Charles A.


#16
whole big market for copper jewelry, specifically as a health
thing! 

Close, Janet - there’s a whole tiny market for copper jewelry. Me,
I’ve been trying to take some reasonable course - copper can affect
the human body, but mostly it doesn’t, at least not much in normal
wear. The real point is to understand that there are reasons beyond
snobbery as to why it’s rarely used in jewelry. Mostly it’s dirty,
it tarnishes immediately, leaves stains and residue on the skin, and
the like. Most people throughout history don’t like it much, for
those reasons.


#17

Just to note that there are a lot of patina solutions that say
"verdigris" or the colour it is imitatiing is that of “verdigris”,
that doesn’t necessarily mean the solution is made from copper
acetate or the crystalline form of true verdigris rather it is more
often a product like’ blue stone’ as is sold in the simples section
of chemist’s (pharmacys in the US) stores,next to products like
rosewater and glycerine,water glass and gum tragacanth, aqua fortis,
acidum boricum, etc… Blue stone is copper sulphate- like the less
refined form sold in garden supply stores, it comes in the form of a"
rock"…which, by the way, used to be used for toothaches (wet the
rock slightly, apply to the cavity, and voila! dead nerve in a bout
10 minutes. it was also used directly in eyes to CAUSE blindness.),
to make home canned (put up in jars) pickles greener, as a pond algae
preventative and 101 other folk-ish uses with that 'grain of truth’
associated with the folk uses. A very common to jewelry example is
Jax brand “verdigris” patina which is made of sal ammoniac and blue
stone ( or ammonium chloride and copper sulfate) and newer bottles of
the stuff are just called Green Patina… So verdigris is not really
made of verdigris… and copper salts which form from skins contacting
copper bracelets are not nearly as noxious as if one applied a wek
solution of verdigris to their skin, and crystals of venus and
crystals of verdigris are slightly different form of copper acetate -
one being copper diacetate and the other copper acetate
respectively… nonetheless, the verdigris is poisonous when
ingested, the risk in handling it is below so I hope this ends this
thread and discussion about the dangers- essentially folks- don’t eat
the stuff, breathe the dust or do anything stupid with pure
crystalline verdigris, or crystals of venus…:and if that weren’t
enough below are the synonyms for verdigris- just so
there isn’t any confusion…rer

Aceticacid, Acetic acidcupric salt;Copper acetate
(Cu(C2H3O2)2);Copper acetate(Cu(MeCO2)2);Copper diacetate;Copper(2+)
acetate;Copper(2+) diacetate;Copper(II) acetate;Crystallized
verdigris;Crystals of Venus;Cupric acetate;Cupric diacetate;Neutral
verdigris;Venus copper

According to OSHA Chemical Safety Regulatory Information Codes: these
codes are highlighted (22-36/37/38-50/53) and apply to copper
sulphate,all below apply to verdigris, and also to its close
relative, crystals of venus (copper diacetate):

S1 Keep locked up.
S2 Keep out of the reach of children.
S3 Keep in a cool place.
S4 Keep away from living quarters.
S5 Keep contents under… (there follows the name of a liquid).
S6 Keep under… (there follows the name of an inert gas).
S7 Keep container tightly closed.
S8 Keep container dry.
S9 Keep container in a well-ventilated place.
S12 Do not keep the container sealed.
S13 Keep away from food, drink and animal foodstuffs.
S14 Keep away from… (a list of incompatible materials will
follow).
S15 Keep away from heat.
S16 Keep away from sources of ignition.
S17 Keep away from combustible material.
S18 Handle and open container with care.
S20 When using, do not eat or drink.
S21 When using do not smoke.
S22 Do not breathe dust.
S23 Do not breathe vapour.
S24 Avoid contact with skin.
S25 Avoid contact with eyes.
S26 In case of contact with eyes, rinse immediately with plenty of
water and seek medical advice.
S27 Take off immediately all contaminated clothing.
S28 After contact with skin, wash immediately with plenty of
soap-suds.
S29 Do not empty into drains.
S30 Never add water to this product.
S33 Take precautionary measures against static discharges.
S35 This material and its container must be disposed of in a safe
way.
S36 Wear suitable protective clothing.
S37 Wear suitable gloves.
S38 In case of insufficient ventilation, wear suitable respiratory
equipment.
S39 Wear eye / face protection.
S40 To clean the floor and all objects contaminated by this
material, use … (there follows suitable cleaning material).
S41 In case of fire and / or explosion do not breathe fumes.
S42 During fumigation / spraying wear suitable respiratory
equipment"


#18

I’ve been following the discussions regarding copper with some
amusement. I take issue your your remarks that there is only a
’tiny’ market for copper jewelry and that most people don’t like it
because it is ‘dirty,’ it tarnishes, leaves a residue on the skin,
etc, etc, etc.

Sterling silver also tarnishes and must be cleaned periodically to
keep it shiny.

In my experience many, many people love the look of copper
jewelry.They love its warm and earthy look. Many people love the way
copper changes color as it oxidizes. Yes, copper does leave a
residue on some people’s skin, and these people may choose not to
wear the copper unless it has been coated. But most people’s skin
does not turn green from wearing copper.

In today’s economy, gold is out of reach for most people (and for
most individual designers), and silver has also become too dear for
many designers to work with and still make a profit.

Copper, brass, and other non precious metals are viable choices for
making jewelry - both for designers and for customers.


#19

Ah yes, the traditionalists note that copper is inferior, but those
of us who like it may have the last laugh yet. The last time we were
in the States we stopped in at the the largest, jewelry chain in
Cincinnati. They were carrying copper jewelry, selling it and spoke
highly of it. Those of us who make it, lacquer it. It doesn’t touch
the skin. It doesn’t turn anyone green. Besides, my customers take
baths. We get all sorts of wonderful colors from copper which you
can’t get from the expensive metals. With the price of copper
jewelry, it doesn’t have to last forever. Because you can have more
of it, you don’t have to wear it all the time and it lasts longer
than you might think. Properly sealed, it doesn’t have to darken,
but sometimes it’s nice to let it age naturally.

We have eight year old copper lamps which were not sealed and now
are developing the most wonderful colors, lavenders, blues, pinks,
reds. If my jewelry matures as these lamps have I’ll be thrilled. I’m
making jewelry to be worn today. To the person who buys it, today is
vastly more important that 100 years from now. American taste seems
to be much less formal now and “laid back” seems to go with the
informality of copper. Remember the days when diamonds in the
daytime were considered tacky? Well it seems that the display of
wealth by wearing expensive jewelry may be the new tacky. If I were
stuck in the traditionalism I started with I’d still be doing silver
and the more expensive expensive metals and stones exclusively.

But like the oil painter who discovered acrylics, this silver smith
has discovered copper and he loves it. My percentage markups are way
up. I don’t have to sit around and wait for something I can make a
killing on to sell. I have the fun of selling it as fast as I can
make it.

Dick


#20
In today's economy, gold is out of reach for most people (and for
most individual designers), and silver has also become too dear
for many designers to work with and still make a profit. Copper,
brass, and other non precious metals are viable choices for making
jewelry - both for designers and for customers. 

I make my living from making gold and sterling items and I sure am
not going to allow the economy to dictate what metals I work with.
You have the control over which market you want to cultivate. The
market does not control you, however your fear can limit your vision.

I have a retail store in it’s 21st year. We have carried brass and
cop= per jewelry over the years, gold and sterling outsells copper,
brass, and titanium by a huge margin. I have local artist that
consign to me in copper and brass, I promote them as much as any
other artist, their work just does not sell as well as sterling and
gold by the same artists.

I am fortunate to have skill and the ability to design jewelry that
people desire and are willing to compensate me for my time at a rate
that allows me to stay in business so far.

My store is not in a mall, not in a strip mall. It is actually in a
small historic business district in a residential neighborhood off
the beaten path.

I am not smart, I have been persistent in my passion to pursue my
vision. For me, rose gold, 14kt, 18kt and 24kt yellow and sterling
are the metals I appreciate most.

I make some pieces that will be heirlooms. Copper and brass are more
like costume jewelry to me and I cannot see anything made from these
metals being passed down. It is not important to me that my work will
be passed down. I just know that it will happen, and some customers
tell me they want something made they can pass down.

Richard Hart G.G.
Denver, Co.