The gold purity of a gold necklace is measured in "karats". Pure, fine gold is 24K gold, which is soft and malleable for a metal. Jewelers add alloys to gold to strengthen the metal so it doesn't scratch easily and lose particle, or mass.
The most common alloys are copper and silver. Please note that different gold jewelry colors use different metal compositions to attain their desired color.
Below are composition percentages for yellow gold necklaces:
10K yellow gold necklace composition:
14K yellow gold necklace composition:
18K yellow gold necklace composition:
Continue to Gold Necklaces Colors