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."

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.

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.

TANZANITE: Found in the 1960's, tanzanite is new and rare discovery that captures magnificent shades of purple, violet and blue. Its crystal structure allows light to enter the stone and divide into two or three sectors which enhances the intensity of color. Tanzanite is an alternate for December birthstones.

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.

IOLITE: Ranging in shades from light blue to violet blue to deep rich blue, the iolite mesmerizes with its ability to change colors when viewed from different angles. Long ago, Vikings relied on this unique gemstone to help guide them at sea.

GARNET: the birthstone of January. One glance at the deep red seeds nestled inside of a pomegranate explains why the word "garnet" comes from the Latin word "granatus," meaning "grain" or "seed." This name was given to the garnet because of its close resemblance to the succulent seed.