Tuesday, November 13, 2007

Why is my gold jewelry cracking?

Several conditions can cause gold jewelry to break.

Manufacturing processes such as stamping, forming, casting, soldering and welding can all cause defects that weaken the piece. This type of defect is usually discovered by quality control inspection and the part or item is rejected before ever leaving the production facility.

Another type of break is mechanical stress.While any metal can crack when bent back and forth several times this isn't usually the case with jewelry unless it is a spring, fastening or other mechanism that receives a lot of flexing.

The most common problem is a result of 'corrosion stress fracturing'.
Very common chemicals in our environment can have a detrimental effect on the integrity of the alloy structure of karat gold especially chlorinated water and salt water.

Gold jewelry alloys are designed to make pure gold more durable and take on an attractive coloration depending on the metals used for the alloy. While pure gold is virtually non-reactive to the chemicals in our environment the 'base' metals composing the alloys are highly reactive. Copper gives gold a reddish tint as in 'rose gold' or 'pink gold' and nickel or palladium give gold it's white color. Silver gives gold a very pale color known as 'green gold'. Usually a rich yellow color is imparted to gold by using a mixture of silver and copper. Other trace metals can be added to improve specific working properties of the alloy for casting, rolling, milling, etc.

The effect of all these metals melted together is a crystal matrix of alloyed karat gold. Imagine this mix of metals as a popcorn ball with peanuts(gold), popcorn(silver) and candy(copper) all bonded together. Now imagine running water over this popcorn 'alloy'. The sugar syrup glue starts softening, the popcorn starts getting soggy and the candy starts melting and staining everything. Eventually the popcorn ball loses its shape and crumbles leaving you with a handful of peanuts!

Karat gold is a little like that example in that the microscopic crystal array is a blend of the metals. The chemicals in our environment do the eroding of the alloys and weaken the structure allowing it to crack. At first, this effect can target crevices in the jewelry or stressed areas from the manufacturing process, however if exposure is prolonged or concentrated enough the entire piece can be affected, weakening and discoloring it.

It is best to avoid wearing jewelry while swimming in salt water, chlorinated pool or spa water or even showering in municipal water.

Thursday, November 8, 2007

“Is this jewelry real? It leaves a mark on my skin.”

Many times discoloration left by jewelry on skin and clothes is possible even with the finest jewelry. Commonly called ‘gold smudge’ by jewelers, there are many possible reasons for this discoloration such as body chemistry and allergy, outside chemical exposure such as cosmetics and body-care products, water treatment chemicals and even air pollution. Microscopic physical abrasion of the jewelry by skin and clothing can also cause ‘smudging’ since fine particles of the metal are being worn away and deposited on the surface rubbing against the jewelry.

Abrasion- Fine dust and even body powder caught on the skin surface and fabrics act as ‘polishing’ agents that rub tiny amounts of metal from jewelry into the wearer’s skin and clothing leaving a stain. Try this test: Take a small piece of cloth and dust onto it some cosmetic powder or talc. Rub the bottom of a ring on the cloth back and forth quickly several times staying on the same area of the cloth. This will usually leave a dark streak on the cloth showing a quick example of ‘gold smudge’.

Chemicals
- Pure gold is a very stable metal that is considered non-reactive for the most part. It takes very strong acids, heat or electric current to break down its crystalline structure. Since it is very malleable it is difficult to design durable jewelry using pure gold. The alloy metals used to create Karat gold, usually silver, copper, nickel, and zinc are highly reactive so they oxidize and are affected by other chemicals very easily. Cosmetics and body products contain vast arrays of chemicals both botanical and manufactured. It is these compounds which can react with the base metals of karat gold alloys and cause tarnish, smudge and even corrosion stress fracturing of the jewelry. It is my personal observation that the essential oils used as scent bases for perfumes and colognes are very good at creating a ‘rainbow’ of different tarnish colors on gold jewelry. Municipal water, swimming pools, spas and salt water all contain chemicals that affect karat gold jewelry. Chlorine and sodium chloride (salt) are especially harmful to gold jewelry if the exposure is long term or concentrated. Taking jewelry off when swimming and bathing is a very good idea. Never clean jewelry in chlorine bleach! Even urban and industrial air pollution can cause tarnishing if extreme enough concentrations.

So while cheap imitation jewelry may ‘turn your finger green’ it may well be that your environment can affect your finest jewelry in a similar fashion. The best prevention is to keep your jewelry clean and away from contaminants.

Sunday, November 4, 2007

Birth of the ClassicGoldsmith's Blog

Well this is something we've been waiting to do for a long time.

Primarily set up with the idea of a Q&A type forum we are going to include many 'how to' and demonstration videos for the handcrafting of jewelry as we get them edited and uploaded.
Bring on the topics! Whether consumer advice, hobby interests, career information or even 'trade secrets', we can get you answers.

Watch for our Information Links and Videos in the near future.