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.

FIXED: A bale that is worked into the actual design of a pendant. Typically seen in slide pendants.

PERIDOT: the birthstone of the month of August, peridot is only found in one color: green. Historians are now convinced that some, if not all, of the emeralds that Cleopatra was famous for wearing were not actually emeralds but deep green peridot stones from Egypt.

PEAR: Similar to the outline of a pear fruit, this is a round shape that comes to a point on one side.

BRILLIANT: A gemstone cut to enhance brilliance without sacrificing much carat weight. Typically has 58 facets.

TOPAZ: Available in a stunning selection of shades, the topaz's sky blue hue is one of the most popular colors for jewelry designs. Once thought to offer protection, today topaz is favored for its durability and affordability. Yellow topaz is the birthstone for November while blue topaz is for December.

DIOPSIDE: Though quite rare, diopside is one of the most affordable green gemstones. This gorgeous newcomer, mined mainly in Siberia, lights up jewelry designs with vibrant shades of green and makes an ideal choice for pendants, rings and earrings. The most popular variety is chrome diopside which features a medium-dark vivid green hue.

SAPPHIRE: A favorite gemstone of ancient priests and royalty, the sapphire radiates sophistication and grace. This prized gem comes in every hue of blue, plus the more unexpected shades of pink, yellow, green and orange, and is September's birthstone.

AMETHYST: A natural variety of quartz, amethyst ranges in color from deep purple to pale lavender, and even to warm greens. Amethyst has been used during meditation to provide a sense of spiritual balance. Amethyst is the birthstone of February.

SQUARE: A symmetrical shape with four equal sides.

CUSHION: A gemstone that features a rounded square shape. The facet arrangement can be either a type of modified brilliant cut or a checkerboard pattern.

CITRINE: A member of the quartz family, citrine symbolizes cheerfulness and prosperity. Its name is derived from the French word citron meaning lemon. This sunny stone comes in colors from lemon yellow to amber brown, with its coloring agent attributed to iron. Citrine is the birthstone for November.