|
||
|
|
|
Gold is the most popular material used in jewelry today. There are many different grades and colors of gold, and consumer tastes vary widely around the world. In its purest form, gold is practically unusable in making jewelry because it is much too soft. To make the gold harder and thus workable into jewelry, it is alloyed with other metals. The process of alloying is simply mixing metals together. Because the value of the jewelry is controlled by the amount of gold in the alloy, a scale was developed to keep track of the amount of gold and other materials, and today this is known as “karats.” The table below indicates some common karat values found in jewelry, and the amount of gold contained in the alloy. The lower the karat value, the more durable, or hard, the jewelry will be, but it will contain less gold.
The choice of material used in the alloying process not only affects the hardness of the gold, but it also affects the color of the gold. The table below lists some of the commonly used metals in alloying with gold, and their effect on color.
For example, to make white gold, a jewelry maker would generally mix Gold with Copper, Nickel, and Zinc. White gold is also often treated with a thin layer of Rhodium to keep its luster. It is important to realize that the choice of alloying material has very little effect on the value of the gold in the jewelry. Platinum is a very rare material, and can be considerably more expensive than gold. Like gold, platinum must be alloyed with other metals to make it suitable for making jewelry. The choices of alloying metals are Iridium, Ruthenium, and Palladium. The choice of alloying metal has no effect on the value of the Platinum jewelry. The amount of alloying material is closely regulated, and generally is limited to 5 or 10% of the overall weight. 95% pure Platinum is labeled as either PLAT 950 or PT 95. 90% pure platinum is labeled as PLAT 900 or simply PLT. Palladium is part of the Platinum family of metals. It has seldom used in jewelry making because of its relatively low oxidizing temperature, but it is making a fashionable recovery as it is about half the weight of Platinum, is similar in appearance, and is much less expensive. One advantage of Palladium over white gold is that its color will not wear off and need to be replated. Many experts believe that Palladium jewelry will increase significantly in value in the near future. Palladium must be alloyed with other metals to make it suitable for making jewelry, typical choices are Ruthenium, Silver, Gallium and Platinum. The choice of alloying metal has little to no effect on the value of the Palladium jewelry. Unfortunately, the labeling of Palladium jewelry has not been standardized, and it is typically just stamped Palladium, if it is stamped at all. It is graded the same as other metals, meaning a 950 grade is 95.0% pure. Most European jewelers do not recognized palladium as a suitable material, and is therefore not hallmarked. Watch out for the unscrupulous jeweler who might sell Palladium jewelry as Platinum. Silver is a common, inexpensive alternative to gold and platinum jewelry. In its purest form, Silver will rapidly oxidize or “tarnish” when exposed to air. For this reason, it is commonly allowed with copper to form a mixture of 92.5% Silver and 7.5% Copper. This is commonly labeled as 925, and nearly all silver jewelry is made from this alloy. Titanium is a relative new comer to the jewelry industry, but is gaining praise for its light weight, durability, and hypoallergenic nature. Jewelry grade Titanium is often an allow containing varying degrees of Aluminum, Vanadium, and Tin. The most common grades of Titanium are listed in the table below.
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||