Blue Synthetic Opal Sea Turtle Pendant Necklace in 18kt Gold Over Sterling. 18"

18KT: Karat (abbreviated kt or K) is a unit that indicates the purity of gold in the metal. 18kt is 75% gold. In Europe, 18K yellow gold is most favored and used in jewelry.

YELLOW GOLD: Gold is a precious metal with a natural yellow color. It is quite soft and often alloyed with other metals to increase its strength. The purity of the metal is indicated by a unit called a "karat," with 24kt having the highest percentage of natural gold.

STERLING SILVER: Also known as "Standard Silver," sterling silver is silver alloyed with other metals to increase the hardness and durability. Generally, sterling is 92.5% silver and 7.5% other metals. Some sterling silver jewelry is plated with 14kt-18kt gold and referred to as "vermeil," or "gold over sterling."

CABLE: One of the most popular and classic of chain styles, created from interlocking oval links unvarying in size.

SPRINGRING CLASP: Invented in the early 1900s this diminutive device is highly effective. It's a hollow circular metal fastener with a spring opening. This keeps the clasp closed.

SYNTHETIC OPAL: A gemstone that is created in a laboratory to mimic the actual properties of a natural opal. Commonly known as "created opal," it features the same fiery color play as a real opal, but is considerably more affordable.

OVAL: An elliptical shape that resembles an egg.

SLICE: A thin, usually flat piece cut from a gemstone. Often has a free-form shape and reveals the natural beauty of a gemstone's interior.