Gold, Platinum, Silver and Other Precious Metals FAQsGold, Platinum, Silver and Other Precious Metals FAQs
- What is a karat?
- What is the difference between a karat and a carat?
- What is the difference between 14K & 18K gold?
- Can I buy jewelry that is pure gold?
- What is used to change the color of gold?
- What is the difference between platinum and white gold?
- What kind of metal is platinum?
- What is Mokume-Gane?
- What is Shakudo?
- What is Sterling Silver?
Pure gold (fine gold) is softer than pure silver but harder than tin. Its beauty and luster are unmatched by any alloyed gold. The extreme malleability, ductility, and softness of pure gold make it practically useless for jewelry applications. The addition of alloying elements (other metals) to gold are used to increase the toughness and hardness of the metal. While almost any metal can be alloyed (melted) with gold, only a select group of metals will not dramatically change the color or make the metal brittle. For example, we never mix indium with gold because it turns gold purple and gives gold the workability of glass.
What is a Karat ?
Over time, certain percentages of gold have become legally recognized "karats." The karat indicates the amount of gold as a percentage of the total, i.e. 24 karat is 100 percent gold. In karated gold, there is a balance of metals in the non-gold percentage called alloys. These metals provide the various colors and hardness of karated gold. 18 karat gold is 18 parts gold and 6 parts alloys such as copper, nickel, silver or zinc. 14 karat gold is 14 parts gold and 10 parts alloy. Gold standards vary around the world. In the United States, 18, 14, and 10 karat gold are the only karats allowed to be sold as karated gold.
What is the difference between 14 karat and 18 karat gold?
18 karat gold means that the metal is 18 parts out of 24 pure gold, or in other words, 75% pure gold. 18 karat gold is the standard for European jewelry. 14 karat gold is 14 parts gold, or 58.5% pure gold. It is the standard for American jewelry.
What is used to change the color of gold?
The addition of alloying elements (other metals) to gold are used to increase the toughness and hardness of the metal, as well as change the color. Adjusting the proportions of coloring agents provides the array of colors on the market. Additional metals enhance properties such as castability, grain size, hardness, corrosion resistance, color, workability, ultimate strength, and others. These additions can dramatically change the properties of the karated metal for better or worse. For example: 18 karat rose gold is 75%, or 18 parts fine gold and 25%, or 6 parts copper. It is the rich red copper combined with the pure yellow gold that creates a warm rosy tone. 14 karat white gold is 14 parts gold and 10 parts white metal, either nickel or palladium. These white metals dominate the color, creating a warm gray tone.
Typical alloying elements and their color effect :
Copper - Reddening
Silver - Greening
Zinc - Bleaching
Nickel - Whitening
Palladium - Whitening
Examples of the compositions of different colors are:
Yellow Gold: copper, silver, zinc
White Gold: nickel, manganese, palladium, zinc, copper
Red (Rose) Gold: copper
Green Gold: silver
A carat is a unit of weight for gemstones, where one carat equals 1/5 of a gram, or 200 milligrams. 142 carats equals one ounce. Carats are divided into 100 units, called points . For example, a half-carat gemstone would weigh .50 carats or 50 points. The important thing to note is that carat is a unit of weight, not a unit of size. A one carat stone that is dense will be smaller than a one carat stone that is less dense. For example, sapphires are denser than diamonds, so a one carat sapphire will be smaller than a one carat diamond.
A karat is not a unit of weight. The word karat refers to the amount of gold in a particular item. Karats are measured in units of 24, where 24 karat gold is pure gold. 18 karat gold is 18 parts gold and 6 parts alloys such as copper, nickel, silver or zinc. 14 karat gold is 14 parts gold and 10 parts alloy.
What is the difference between Platinum & White Gold?
Platinum is a precious metal that costs more than gold. It usually is mixed with other similar metals, known as the platinum group metals: iridium, palladium, ruthenium, rhodium and osmium. Platinum is extremely dense, and is much heavier than gold or silver. Platinum has a remarkably high level of durability so it does not wear or tarnish like other metals. White gold is rhodium plated to give it the same white look as platinum, but eventually the rhodium wears off and the white gold takes on a yellow cast. White gold jewelry should be rhodium plated every few years to maintain its whiteness. Platinum does not yellow or tarnish and maintains its white appearance with little maintenance and can develope a hazy patina over time.
Platinum is not susceptible to problems like stress cracking or corrosion as can be the case with white gold. Though platinum can scratch, it is more durable than white gold and does not wear down or abrade like gold. Scratches can easily be removed by buffing, and all that is required to maintain platinum is to soak it in a mild solution of soap and warm water followed by a gently rubbing with a soft bristled brush.
Platinum is considered to be the "most precious" of the precious metals. Platinum is your metal of choice, when only the best will do. Rarer than gold, stronger and more enduring - platinum is also the choice of jewelry designers for fine heirloom quality jewelry.
Platinum History: Platinum evokes the future through the cool gray color and technological uses, but it also recalls the past. In the 1890's the world renowned Louis Cartier introduced the metal as a setting, and made it part of his most exquisite creations for kings and millionaires. During the first 40 years of the twentieth century, platinum was the preferred metal for wedding and engagement rings and was almost always used to enhance the beauty of diamonds and other gemstones. However, for the duration of World War II, platinum was declared a strategic material and its use in most non-military applications was prohibited.
1. Due to the unusual characteristics of this metal, a platinum smith must have a different set of tools than a goldsmith. For instance, platinum melts at 3225 degrees Fahrenheit, compared to fine gold which melts at 1945. 2. Platinum is more scarce than gold - The annual supply of platinum is only about 130 tons - which is only 6% (by weight) of the total Western World's annual mine production of gold.
3. Approximately 10 tons of ore must be mined to produce one pure ounce of platinum. Furthermore, the total extraction process takes six long months.
4. All the platinum ever mined throughout history would fill a room of less than 25 cubic feet.
5. Platinum is even heavier than gold because it is about 11% more dense. One cubic foot weighs around 1,330 pounds.
6. Platinum has many more industrial uses than either silver or gold. In fact more than 50% of the yearly production is consumed (read destroyed) by industrial uses.
7. Also unlike gold, there are no large inventories of above-ground platinum. Therefore, any breakdown in the two major supply sources would catapult the price into orbit.
Palladium is one of six metals in the platinum family. It has similar characteristics of platinum, such as high melting temperature, cool gray color, durability and rarity, however, it is much less dense (lower specific gravity). Palladium is a soft silver-white metal that resembles platinum. It is the least dense and has the lowest melting point of the platinum group metals. Palladium is the metal of choice to mix with pure gold to create the finest white gold. Like platinum, it will develop a hazy patina over time.
What is Mokume-Gane?
Mokume-gane is a mixed-metal laminate with distinctive layered patterns. Literally translating as "wood eye metal", the name was borrowed from one type of pattern created in the forging of swords and other edged weapons. Two or more metals are stacked in alternating sheets and fused together. The billet is then forged and formed and filed to reveal an interesting pattern of the layers of sheet.
Shakudo is a Japanese alloy made of 96% copper and 4% fine gold. It has a natural dark patina and, if worn away by sand or chemicals, it will naturally re-darken through contact with water, air, the skin, and chemicals such as ammonia.
Sterling Silver is the whitest of all the metals. Fine silver is generally too soft for most jewelry applications. Sterling Silver is a mix of 92.5% fine silver and 7.5% copper. Silver products sometimes may be marked 925 , which means that 925 parts per thousand are pure silver. 99.9% silver is called "Fine silver." Sterling components and jewelry made in the USA are often stamped "Sterling." Goods made for international trade are often marked "925" indicating the 92.5% fineness. "Coin" silver is used in some countries and could be marked "900" or "800" depending on fineness.