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We buy Gold & Silver Coins & Scrap

Why Does Gold Discolor? 

You may think that faulty manufacturing or under-karating might be the problem when a ring turns, blackening or discoloring either the skin and clothing, or the jewelry itself.  However, that is not the case.
  The most common reason for jewelry turning your skin black is metallic abrasion, caused by makeup on skin or clothing.  Cosmetics often contain compounds harder than the jewelry itself, which wear or rub off very tiny particles of the precious metals.  Very finely divided metal always appears black, rather than metallic, so it looks like a jet-black dust.  When this dust comes into contact with absorbent surfaces such as skin or clothing, it sticks, forming a black smudge.

  To prevent this, a person should try switching cosmetics.  If this is not possible, it is recommended to remove rings and other jewelry while applying makeup, and then clean the skin areas in contact with the jewelry with soap and water.
  Another cause of discoloration is the actual corrosion of the metals.  Gold itself does not corrode, or oxidize, but its primary alloy materials of silver and copper will do so forming very dark chemical compounds under moist or wet conditions.
  When a person perspires, fats and fatty acids released in the perspiration can cause corrosion of 10 or 14-karat gold, especially when exposed to warmth and air.  This problem can be worse in seacoast and semitropical areas, where chlorides combine with the perspiration to form a corrosive element that discolors skin.  Even smog fumes will gradually attack jewelry, and are evident as a tarnish that rubs off on the skin.
  Under these conditions, it is suggested that a person remove their jewelry often, and use an absorbent powder, free of abrasive compounds, on skin that comes into contact with the jewelry.
  Sometimes, the actual design of the jewelry can be an influencing factor.  Wide shanks have more surface area to contact abrasives or corrosives.  Concave surfaces inside a shank form natural collection points that trap moisture and contaminants, also causing a type of dermatitis.
  A person should remove all rings before using soaps, cleaning compounds, or detergents, or going into pools, and clean their rings frequently.  As well as solving the problem, a person will be amazed at how much better their rings will look!
  If success is not achieved with these corrective measures, it is recommended that a person switch to 18-karat gold or platinum jewelry.  The lower alloy metal content of 18-karat gold, 25% versus about 41.5% (14K) to 58.3% (10K), significantly reduces the problem, and the use of platinum should eliminate it completely. 

Alloy Factors

Stress corrosion is very common in low karat alloys, 10K, 41.7% gold or less.  In alloys with gold content of 18K, 75% gold or greater this problem is almost non-existent.  Stress corrosion is also common in white gold, due to the presents of nickel in many of the alloys. 
 
Stress Factors

Technically, Stress is fluctuating strains in the metallic structure that work against each other eventually leading to what we see as a stress crack.  Mechanical deformation is a primary source of stress including bending of the ring shank.  It is no different from bending a copper wire back and forth, eventually it will stress and break.

Corrosion
Corrosion is the reduction of metals to a metallic salt.  In gold jewelry, aqueous or gaseous environments can cause corrosion.  Stressed areas are possible sites of fracture, opening entry routes for corrosives.  Mercury is a great example of wet metal corrosion, as is the exposure of a copper-based alloy to liquid bismuth.  The liquid metal migrates through the metallic structure of the solid metal structure, propagating a fast fracture.  Chlorine is extremely detrimental to gold karated metal alloys.  Special should be taken with detergents, cleaners, and other industrial or household formulas.  Chlorine and other chemical levels can be increased by evaporation, leaving a more concentrated deposit on your jewelry.  This makes spas and swimming pools undesirable for gold jewelry.

The 10 Karat Myth
 
Webster defines the word myth as any fictitious story or account of unfounded belief.  The 10-Karat Myth goes this way, What you need is a 10 Karat wedding band!?  Why, you ask?  Because 10 Karat gold is harder, it won't wear out like a 14 Karat band will.  Wear Out!  Just what exactly is the poor soul planning to do with the wedding band that would wear it out?  Maybe they're going to hold their hand out the car window and drag the ring on the interstate?  We don't think so!
  If consumers are concerned about misshaping the ring because they work with their hands, the thickness of the ring should be of greater concern than the karat.  Be certain the band is wide enough and thick enough (not lightweight) to hold up under the appropriate circumstances.  Comfort fit bands are good in these situations because of their relative thickness.  Of course, there are different perspectives on the advantages and disadvantages of 10 Karat, unfortunately much of the argument supporting lower-karat sales is based on a lack of accurate information.  We have poured over the mythical advantages of 10 karat and were able to come up with only one the cost to the consumer.  It is cheaper!  The list of disadvantages of the less-noble 10-Karat metal is considerably longer.  Because 10 Karat is less than ½ gold by weight (41.7% to be exact), this means that more than 50% of the ring weight is made of base metals.    This increased base metal content makes 10 karat less resistant to tarnishing, less resistant to stress corrosion and more likely to produce an allergic reaction in those prone to base-metal allergies.
  When it comes to hardness and durability we find that there is virtually no advantage between 10 Karat and 14 Karat provided they have been properly annealed. 


Ten Quick Facts About Fine Jewelry
 
·         One ounce of gold can be drawn into a wire more than 50 miles long or beaten flat to cover over 100 square feet.

  ·         To be called silver in the United States, the purity of silver jewelry must be at least 92.5% pure silver.

  ·         Unlike other gemstones, a diamond is composed of one element-pure carbon-crystallized under tremendous heat and pressure.

  ·         Rubies in large sizes (over 3 carats) and high qualities are far more rare than diamonds.

  ·         The most desirable tone for most colored gemstones is medium to medium-dark.

  ·         Amethyst and citrine are both from the quartz mineral family.

  ·         Tourmaline is the only gem that occurs naturally in every hue of the rainbow.

  ·         Opals are softer than most other gemstones and should be treated with great care.

  ·         Chlorine can damage the alloys in gold and silver jewelry.

  ·         Cultured pearls are relatively soft and should only be cleaned with a mild soap and water solution.
Gold Miner Jewelers
2737 US Highway 45
Antigo, WI 54409
715-627-4747
gmb57@netzero.net
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