Gold

The word gold, used by itself, means all gold or 24 karat (24K) gold. Because 24K gold is soft, it’s usually mixed with other metals to increase its hardness and durability. If a piece of jewelry is not 24 karat gold, the karat quality should accompany any claim that the item is gold. The karat quality marking tells you what proportion of the gold is mixed with other metals. Fourteen karat (14K) jewelry contains 14 parts of gold, mixed in throughout with 10 parts of base metal. The higher the karat rating, the higher the proportion of gold in the piece of jewelry. Most jewelry is marked with its karat quality, although law does not require marking.

Solid Gold refers to an item made of any karat gold, if the inside of the item is not hollow. The proportion of gold in the piece of jewelry is still determined by the karat mark. Jewelry can be plated with gold ion a variety of ways. Gold Plate refers to items that are mechanically plated, electroplated, or plated by any other means with gold to a base metal. Eventually, gold plating wears away, but how soon will depend on how often the item is worn and how thick the plating is. Gold -filled, gold overlay and rolled gold plate are terms used to describe jewelry that has a layer of at least 10 karat gold mechanically bonded to a base metal. If the jewelry is marked with one of these terms, the term or abbreviation should follow the karat quality of the gold used (for example, 14K Gold Overlay or 12K RGP). If the layer of karat gold is less than 1/20th of the total weight of the item, any marking must state the actual percentage of karat gold, such as 1/40 14K Gold Overlay. Gold Electroplate describes jewelry that has a layer (at least .175 microns thick) of a minimum of 10 karat gold deposited on a base metal by an electrolytic process. The terms gold flashed or gold washed describe products that have an extremely thin electroplating of gold (less than .175 microns thick). This will wear away more quickly than gold plate, gold-filled or gold electroplate.

Platinum

Platinum-a precious metal that costs more than gold-usually mixed with other similar metals, known as the platinum group metals: iridium, palladium, ruthenium, rhodium and osmium. Different markings are used on platinum jewelry as compared with gold jewelry, based on the amount of pure platinum in the piece. The quality markings for platinum are based on parts per thousand. For example, the marking 900 Platinum means that 900 parts out of 1000 are pure platinum, or in other words, the item is %90 platinum and %10 other metals. The abbreviations for platinum - Plat. or Pt. - also can be used in marking jewelry.

Items that contain at least 950 parts per thousand pure platinum can be marked simply platinum. Items that have at least 850 parts per thousand pure platinum can be marked with the amount of pure platinum and the word platinum or an abbreviation (for example, 950 Platinum, 900 Plat. or 850 Pt.). Jewelry that contains less than 850 parts per thousand pure platinum, but has a total of 950 parts per thousand platinum group metals (of which at least 500 parts is pure platinum), may be marked with both the amount of pure platinum and the amount of other platinum group metals in the piece. Foe example, the marking 600 Plat. 350 Irid. means that the item has 600 parts per thousand (60%) platinum, and 350 parts per thousand (35%) iridium, totaling 950 parts per thousand of platinum group metals, and 50 parts per thousand (5%) other metals.

Silver

The words silver and sterling silver describe a product that contains 92.5% silver. Silver products may sometimes be marked with 925, which mean 925 parts per thousand are pure silver. Some jewelry may be described as silverplate: a layer of silver is bonded to a base metal. The mark coin silver is used for compounds that contain 90% silver.