Guest Author - Diane Geisel
Because of the softness of pure (24k) Gold, it is usually alloyed with base metals for use in jewelry, altering its hardness and ductility, melting point, color and other properties. Typically 22k, 18k, 14k or 10k, contains higher percentages of copper, or other base metal alloys giving the gold more strength. Gold alloy with silver added appear greenish-yellow and is referred to as green gold. 18k gold containing 25% copper is found in antique and Russian jewelry. It has a distinct copper cast creating rose gold. White 18k gold containing 17.3% nickel, 5.5% zinc and 2.2% copper is silver in appearance.
Many people are not aware of the differences between "Gold-filled" and Gold-plated" jewelry. Basically, gold-filled jewelry is of a higher quality and is made with 100 times more gold than gold-plated. It is also sometimes referred to as "Rolled Gold". Like solid gold, gold-filled products are regulated by the government and must be at least 5% gold by weight. Gold-filled wire is a professional jeweler's quality wire. To make rolled gold 14kt gold-filled wire is made by forming a tube of solid 14kt gold that is "filled" with a base metal. The gold is bonded to the base metal with heat and pressure. The base metal is also gold in color and is made up of almost the same mixture. The exterior of the product is solid 14 kt gold and everything you can see or touch is a solid layer of 14kt gold. This is why it will never tarnish, chip or wear off. 14Kt Gold-filled jewelry was worn extensively in the Victorian Era. Many of these Heirloom pieces are still handed down through genrations and are considered highly collectible. Gold-filled jewelry is economical & durable -- you enjoy the look and feel of gold at a fraction of the cost.
Nothing compares to the unique clean, bright sparkle of Silver. Sterling is made from 92.5% silver. It can also contain nickel, which can cause an allergic reaction for some people, or copper. It tarnishes with age, but can be restored with a silver polish. Argentium sterling silver has appeared in recent years, formulated to lessen firescale or to inhibit tarnish, and this has sparked heavy competition among the various manufacturers, who are rushing to make claims of having the best formulation. However, no one alloy has emerged to replace copper as the industry standard, and alloy development is a very active area.
Copper is a pretty reddish color in the beginning but will patina or tarnish over time but the original color can be restored/protected by copper polish or a quick dip in simple vinegar. It is a very common base metal mixed with other metals for making jewelry. Copper can be enameled. A center of soft copper coated with a layer of jewel-tone plastic allows different color choices. One of my favorite items to collect is Matisse jewelry from the 1950ís. This jewelry is well known for copper enamel combination.
Palladium has been used in jewelry since 1939, as an alternative to platinum or white gold. Palladium is one of the three most popular metals used to make white gold alloys. (Nickel and silver can also be used.) Palladium-gold is a more expensive alloy than nickel-gold, but it's naturally hypoallergenic and holds its white color better. When platinum was declared a strategic government resource during World War II, many jewelry bands were made out of palladium. As recently as September 2001, palladium was more expensive than platinum and rarely used in jewelry also due to the technical obstacle of casting. However, the casting problem has been resolved and its use in jewelry has increased because of a large spike in the price of platinum and a drop in the price of palladium
Platinum finds use in jewelry, usually as a 90-95% alloy, due to its inertness and shine. In watchmaking such as Rolex and other companies use platinum for producing their limited edition watch series. Watchmakers highly appreciate the unique properties of platinum as it neither tarnishes nor wears out. On average the cost of platinum is twice that of gold in steady economic times but can sink below gold during periods of economic uncertainty.
Rhodium is used as an alloying agent for hardening and improving the corrosion resistance of platinum and palladium. When electroplated on white gold and platinum to give it a reflective white surface this becomes known as rhodium flashing. It also may be used in coating sterling silver in order to strengthen the metal from tarnish, as a result from the copper compound found in sterling silver. Solid (pure) Rhodium jewelry is very rare, due more to the metal having the dual characteristics of a high melting point and poor malleability (making such jewelry very hard to fabricate) than to the metal's high price.
Pot metal is a slang term that refers to alloys that consist of inexpensive, low-melting point metals used to make fast and inexpensive castings. There is no scientific metallurgical standard for pot metal; common metals in pot metal include zinc, lead, copper, tin, magnesium, aluminum, iron, and cadmium. The primary advantage of pot metal is that it is quick and easy to cast. It is referred to as white metal, die-cast zinc, or monkey metal but on the downside can become bent, distorted, cracked, and pit with age.
Bronze is a metal alloy consisting primarily of copper, usually with tin as the main additive, but sometimes with other elements such as phosphorus, manganese, aluminum, or silicon.
Brass has a lovely yellow-gold color. It is an alloy of copper and zinc. It will darken over time, but can be restored/protected with brass polish or a quick dip in simple vinegar. Often it is used in Czechoslovakian jewelry.
Stainless steel is also used for jewelry and watches. The most common stainless steel alloy used for this is 316L. It can be re-finished by any jeweler and will not oxidize or turn black.
Anodizing niobium creates an oxide layer; the thickness of this layer creates colors. It is perfect for jewelry because it contains no nickel (which can cause reactions to gold and silver) and is 22% lighter than silver.
Aluminum is a lightweight metal that is light silver in color.
Pewter is a lead alloy.
Sterling Vermeil is Sterling silver that is dipped in gold plating.
Titanium's inertness and ability to be attractively colored by anodizing makes it a popular metal for use in jewelry. Titanium's durability, lightweight, dent- and corrosion- resistance makes it useful in the production of watchcases.
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