Precious Metals Guide

Traditional metals used in jewelry are the “noble metals”: silver, gold and the platinum metal group (including platinum and palladium). Noble metals are so called because of their ability to withstand corrosion and oxidation and their chemical stability. Today's jewelry is more varied and versatile than ever. This is partly due to the use of new types of metals and alloys used to make jewelry.

Through the use of alloys, two or more metals or elements can be combined to give the resulting metallic substance certain properties that are different from its component metals. The primary purpose of alloys in jewelry is to give metals more desirable characteristics. For example, pure gold (24 karat gold) is too soft for prolonged wearing and would scratch easily. Most gold jewelry is either 14 karat gold or 18 karat gold which consists of gold mixed with other alloys, usually silver, nickel, copper or zinc. Sterling silver is silver mixed with alloys to make it stronger. Sterling silver is 92.5% pure silver usually mixed with 7.5% copper.

Metal Purities

Jewelry Classification	Purity	Noble Metal / Common Alloys
24 karat (24k) gold	99.90%	Pure gold
18 karat (18k) gold	75.00%	Gold with nickel, copper or zinc alloy
14 karat (14k) gold	58.33%	Gold with nickel, copper or zinc alloy
10 karat (10k) gold	41.66%	Gold with nickel, copper or zinc alloy
Silver	99.90%	Pure silver
Sterling Silver	92.50%	Silver with copper alloy

Precious Metal Characteristics

Metal	Hardness level (Mohs scale)	Common Alloys	Pros	Cons
24k yellow gold	2.5		brilliant luster	too soft for most jewelry
18k yellow gold	2.75	silver, copper, zinc, nickel, palladium	alloys used make gold more durable for everyday wear	nickel alloy can have allergenic properties
14k yellow gold	3-4		alloys used make gold more durable for everyday wear	nickel alloy can have allergenic properties
white gold	2.8-4.0	silver, palladium, nickel	less expensive alternative to platinum	can have allergenic properties; rhodium plating will eventually wear off
silver	2.5	copper	low price point	susceptible to scratches
platinum	3.5	ruthenium, iridium, platinum	hypoallergenic, will retain white color	susceptible to scratches, prongs can bend
palladium	4.5	ruthenium, iridium	hypoallergenic, maintains natural white color, great luster enhances gems, naturally strong metal, lighter than platinum	susceptible to scratches, more sensitive to acids, won't take a high polish well
tungsten carbide	9	carbon	hypoallergenic, low price point, maintains white color forever, looks great after years of wear	not a precious metal, can chip or shatter, can oxidize; cannot be sized
tungsten	7.5		hypoallergenic, resists scratches, especially useful for brushed jewelry designs	not a precious metal; cannot be sized
stainless steel	6.5	carbon, iron	resists corrosion and staining	not a precious metal; cannot be sized
titanium	6	aluminum, iron, tin	hypoallergenic, high tensile strength, resists corrosion, light weight	susceptible to scratches; cannot be sized