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Jewelry Metals Continued - Gold Fill - Platinum - Silver


Gold-filled jewelry

… also known as "rolled gold" or "rolled gold plate" is composed of a solid layer of gold bonded with heat and pressure to a base metal such as brass. Some high quality gold-filled pieces have the same appearance as 14 karat (58%) gold. In the USA the quality of gold filled is defined by the Federal Trade Commission. If the gold layer is 10 kt fineness the minimum layer of karat gold in an item stamped GF must equal at least 1/10 the weight of the total item. If the gold layer is 12 kt or higher the minimum layer of karat gold in an item stamped GF must equal at least 1/20 the weight of the total item. The most common stamps found on gold-filled jewelry are 1/20 12kt GF and 1/20 14kt GF. Also common is 1/10 10kt. Some products are made using sterling silver as the base, although this more expensive version is not common today.

"Double clad" gold-filled sheet is produced with 1/2 the thickness of gold on each side. 1/20 14Kt double clad gold-filled has a layer on each side of 1/40th 14Kt making the total content of gold 1/20. The thinner layer on each side does not wear as well as single clad gold-filled.

The Federal Trade Commission allows the use of "Rolled Gold Plate" or "R.G.P". on items with lower thicknesses of gold than are required for "gold-filled." A 12 kt gold layer that is 1/60 the weight of the total item is designated as 1/60 12kt RGP. This lower quality does not wear as well as gold-filled items.

Gold-filled items, even with daily wear, can last five to 30 years but will eventually wear through. The gold layer on gold-plated jewelry varies greatly depending on manufacturer, so there is no single, simple comparison. Gold-filled items are 50 to 100,000 times thicker than regular gold plating, and 17 to 25,000 times thicker than heavy gold electroplate (sometimes stamped HGE or HGP—usually found on flashy cubic zirconia "cocktail rings").

  

Platinum

 

The name Platinum is derived from the term ‘platina del Pinto’ which means little silver of the Pinto river. In its natural form it is a gray-white metal and one of the rarest elements on earth 80% of the worlds production coming from South Africa.

Like gold it has a remarkable resistance to corrosion, and has a higher melting point then gold. It is scarcer than gold with only a few hundred tonnes produced annually and there for considered a high value precious metal usually of greater monetary value then gold.

It is a lustrous metal and extremely malleable not oxidizing an any temperature. Due to its density resistance to wear, it is much more difficult to use than gold, in the creation of jewelry, melting at a much higher temperature. Casting platinum is an art in itself requiring specialized techniques and skill. The jewelry tools and polishes used in platinum jewelry manufacturing are much more susceptible to wear and tear.  Being a white metal that doesn’t fade or  tarnish is well suited for making fine jewelry.

Platinum in jewelry is usually 90–95% of the alloy and unlike white gold which is often plated with Rhodium to give its shiny silver color, Platinum’s color is naturally white an lustrous when polished with minute surface scratches called its patina.

Due to a higher density then gold, Platinum is 11% denser then fine gold and 42% denser then 18K gold. So a ring weighing 4.5 Grams in 18K gold will weigh almost 6.40 Grams in Platinum.


Silver
 

 

Silver often used in jewelry creation is a very pliable and slightly harder than gold. With its brilliant white metallic luster it can be brought to a very high state of polish

Contrary to popular perception, Silver is stable in pure air and water, however it tarnishes when exposed to air or water containing ozone or hydrogen sulfide, the latter forming the a black layer of silver sulfide which can be cleaned with silver cleaners and even some house hold detergents. Silver jewelry that is worn or kept in the sea side with a higher level of humidity, will naturally tarnish at a higher rate due the higher concentration of ozone and hydrogen sulfide in the air.

Silver is dramatically affected by air pollution, notably what are known as sulfides (sulphides). Fumes from cars,  electricplants burning coal, generating air pollution such as sulfur dioxide, pollutes the air and will tarnish silver much faster.

Tarnishing will first turn silver yellow, then form golden patches, and then a purplish film, finally turning dark grey and even black. By the time it reaches this stage the damage can be irreversible. If you live in a humid areas where is there is a high concentration of pollution or near a power plant, be careful to keep your silver jewelry clean. Don’t let your silver jewelry or cutlery for that matter come in contact with eggs which are rich in sulfides, as they will quickly tarnish.

The obvious advantage of silver is that is a fraction of the cost of gold or platinum and if kept clean and protected, will maintain a beautiful luster.

Jewelry and silverware are traditionally made from sterling silver (standard silver), an alloy of 92.5% silver with 7.5% copper. In the US, only an alloy consisting of at least 90.0% fine silver can be marketed as "silver" (thus frequently stamped 900). Sterling silver (stamped 925) is harder than pure silver, and has a lower melting point (893 °C) than either pure silver or pure copper. Britannia silver is an alternative, hallmark-quality standard containing 95.8% silver, often used to make silver tableware and wrought plate. Sterling silver jewelry is often plated with a thin coat of .999 fine silver to give the item a shiny finish. This process is called "flashing". Silver jewelry can also be plated with rhodium (for a bright, shiny look) or gold.

Silver is much cheaper than gold, though still valuable, and so is very popular with jewelers who are just starting out and cannot afford to make pieces in gold, or as a practicing material for goldsmith apprentices. Silver has also become very fashionable, and is used frequently in more artistic jewelry pieces.

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