Opal and 2.90 ct. t.w. Black Spinel Cross Pendant Necklace in Sterling Silver. 18"

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.

OPAL: With an iridescent luster that can reveal a beautiful kaleidoscope of color, the opal has inspired many myths and legends. A white opal with swirls of soft pastel shades is popular for jewelry, but opals also come in black and blue. Opal is the gemstone for October birthdays.

OVAL: An elliptical shape that resembles an egg.

SPINEL: This rare and durable gemstone, found in a beguiling shade of inky black, catches the eye when set in rings, bracelets, necklaces and earrings. Spinel is also found in captivating tones of pink, purple and green. The red variety is beautiful in its own right and in ages past it was mistaken for a ruby.

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