How does jewelry
'turn black' and why is it one of the top concerns of many jewellery wearers?
Let's have a good crack at this issue.
The 'Black' Sheep
There is a variety of jewellery crafting techniques. Nonetheless the
components involved are generally categorized into beads and 'other parts'.
Beads basically last very well
although certain types are not colour fast. Others may react badly with chemicals or peel
over time.
That said, it is the 'other parts' that are more likely to generate quality
issues. And these issues usually arise from the use of metal.
The Enemy - Tarnish
Many metals tarnish. Tarnish is a layer of corrosion that develops over
reactive or semi-reactive metals as they undergo oxidation.
Tarnish is somewhat like rust, but with a slower rate of occurrence. It is
mainly caused by chemicals in the air and sweat.
Tarnish appears as a gray or black film over
the metal. When a piece of jewelery 'turns black', it is a result of tarnish
forming on its metal parts.
The photograph on the right shows two ear wires.
The ear wire on the left is new and looks shiny and bright. The one on the right
shows how the ear wire will look after months of exposure to air and sweat.
A bad case of tarnish has developed and some say it has 'turned black'.
Plating as a Low Cost Solution
Often, modestly priced jewelry deal with the problem of metals tarnishing
through plating - a thin coat of more inert and
attractive looking metal applied to another base metal.
Plating varies widely in materials and quality. One drawback is
that they will likely wear off through wear and tear. The good ones can last
surprisingly long though.
When the plating wears off, the base metal beneath
is thereafter exposed. Base metals may be dark coloured or they may tarnish badly as
their protection is gone. Again, in this instance, it has 'turned black'.
Precious Metals as Solution
A solution in the realm of handcrafted jewelery involves precious metals - usually
silver and gold. It's a solution we have adopted as well. Details are explained
in lessons 6 and 7.
Working with silver and gold alone will not satisfy us. There are so many
varieties of metals and materials out there and they provide us with endless
possibilities.
There must be a way
After loads of hard work in research
and experimentation, we were able to achieve satisfactory to amazing results
with non-precious metals.
There are mainly two issues to tackle:
wear and tear
tarnish caused by environmental chemicals
Wear and tear
Breakthrough Discoveries
There are non-precious metals and alloys that are very much chemically inert. We
have found a few that are suitable for jewellery crafting. (details in lesson 5)
There are parts and components we have discovered that are of this nature as
well. But there are too few of these to produce a significant range of jewellery
and designs.
Outstanding Plating
Plated materials are unavoidable. Not
that we want to avoid them as they provide possibilities otherwise unachievable.
One wonderful discovery is an amazingly tough plating that offers many colours.
The colours are permanent. They do not react to anything we have tormented
them with. It seems you will have to scratch the plating with sharp objects or
they will last and last.
Not all parts of a jewelry piece are subjected to a lot of friction with bodily
parts. An example will be what's below the ear wire of an earring.
It's important
for the ear wire to be tough and lasting. Not as critical when it comes to what
goes on below it. For such parts, it is still acceptable to use materials less
hard-wearing.
Tarnish caused by environmental chemicals
First of all, we all sweat differently. Chemical contents in sweat vary so
widely among people, the contrast is startling.
We know of people who tarnish
their silver jewellery within two hours with their perspiration.
All of us
punish our jewelry differently according to what oozes out from the pores of our
skin. So, along with the sweat and salts from our skin, the air, food and the
various chemicals we routinely come in contact with all contribute to the
encouragement for metals to oxidize.
Rhodium Plating
Jewellery crafters, who choose to work with bright, shiny plated metal parts
and wish to offer a higher quality product, often turn to an element known as
rhodium.
A rare silvery-white hard metal, rhodium is a member of the platinum group.
Rhodium metal does not normally form an oxide, even when heated.
It is the most expensive
precious metal. Due to the price factor, it is generally utilized for plating only.
Jewelery parts (we call them findings) plated with rhodium is a lot more
expensive.
Brilliant and gorgeous, they have an expensive look as well. Good
quality rhodium plating continues to look wonderful even when subjected to harsh,
environmental abuse.
All it needs is a little help through
occasional wiping and polishing. But here's the caveat - good quality rhodium plating.
Strange Findings
Both pendants on the left feature rhodium plated findings.
The one on the
left is new and the one on the right has been subjected extensively to tarnish
inducing chemicals.
It did not tarnish as easily as cheaper findings would but
what happened to it is not normally expected of rhodium, and it was expensive.
4 Grades of Rhodium Plating
(our private ratings)
We sample every batch of findings we intend to craft into jewellery by
testing the specimens intensively under varied conditions to predetermine their
ability to resist oxidation and thus tarnishing.
With rhodium plating, we have
categorized the different qualities we have encountered into four groups:
Grade A – Do not tarnish at all.
Grade B – Shows only traces of blemish. Very good,
considering the hell we put it through.
Grade C – Turns yellowish or exhibit a mild case of
tarnish
Grade D – 'turned black' although not as severely as
cheaper materials would
Can't Count on Them. Can't
Count on Anything
What's very confusing and unsatisfying is that there are
supposedly guiding factors to the quality of this form of plating:
Price – higher prices should lead to better quality
Specification – those with better specifications
should offer better quality
Source – some countries are reputed to make them better
Factory – if a number of products from a factory were
tested to be good, others should showcase similar qualities
Comments from experienced sources – suppliers
confidently assuring certain batches of goods are really top quality
All the factors above are unreliable. We can never tell if
we have purchased a gem or a dud. We can't tell because they all look great,
rhodium great.
Testing Shows Us the Truth
Putting them through rigorous tests is the only way to see their
true colours.
Agalil's quality policy is to use rhodium plated findings
of Grade A and B only. This yardstick applies to all other bright and shiny type
of plated materials –
they must be resistant to oxidation as well as Grade B rhodium plating at the
minimum.
Solutions to Jewelry Turning Black
As you progress through the lessons, you shall learn about some of the
different solutions to combat jewelry tarnishing.
So that you'll have examples to look at, one solution is enameling.
Enamel plating will prevent oxidation as long as the plating is in place. The
key is in discovering strong, quality enamel plating.
