PLATINUM | GOLD | STERLING SILVER | TITANIUM | MIXED METALS

Metals - GOLD

Gold (Kt.)
Mineral Information: Gold
Chemical Composition: Au

No precious metal is as legendary and beautiful as gold. Gold has been used as a monetary standard throughout the history of mankind, and ancient gold jewelry and ornaments dating back many centuries are still admired throughout the world.

Because pure gold is so soft and pliable, jewelry made of it would too easily bend and distorted in wearing. To solve this problem, jewelers use alloy base metals to form karat gold (not the carat used to measure diamond weight). Alloying increases gold’s hardness and provides the ability to produce different colors (white, rose, green).

The purity of the karat gold depends on the percentage of the relative amount of gold in an alloy. The karat measurement determines the percentage of gold to other metals on a scale of 1 to 24, with 24 karats being pure gold. The term "plumb gold" means any karat of gold that is alloyed within a strict, exact tolerance.

24 Kt = 24/24 = 100% pure gold
22 Kt = 22 / 24 = 93.30% pure gold
18 Kt = 18 / 24 = 75.00% pure gold
14 Kt = 14 / 24 = 58.33% pure gold
10 Kt = 10 / 24 = 41.67% pure gold

Colors of karat gold depend upon base metals used in the alloy. These include silver, copper, nickel, zinc, platinum, and palladium. Green, pink and yellow golds are made by mixing silver or copper with the gold. More copper gives pink (or "rose") gold its color, while 18 Kt green gold is caused by using a more concentrated silver misture. White gold contains about 10 to 20 percent nickel, plus zinc, copper, platinum, and palladium. These alloys make white gold harder and tougher to work than yellow gold.

The international weight measurement of gold is the troy ounce. One troy ounce of gold equals 31.1 grams.

Gold Jewelry Care: Gold alone is impervious to tarnishing, and it takes strong and dangerous chemicals to dissolve it. Some alloys, mostly pink gold and the 10 Kt alloys, can darken over time. Customers should be warned to keep alloyed gold jewelry away from bleach, pool chlorine, cosmetics and perfumes.

Quality Marks: Hallmarking in America began in Baltimore in 1814. American manufacturers customarily use the numbers in their quality stampings. Foreign manufacturers stamp their products with a three-digit number which gives the gold content as parts per thousand. 750 inside a foreign-made ring indicates 18 karat gold, 585 corresponds to 14 Kt gold. The Federal Trade Commission prohibits the use of the word "gold" in America for any alloy below 10 Kt.