One of the oldest known gemstones, turquoise has been mined for millennia. Ranging in color from a robin’s-egg blue to vibrant greenish blue to intense bluish green and all shades between, this gemstone’s popularity crosses cultural and continental boundaries. Turquoise may contain veining known as matrix. When the matrix forms an intricate and consistent pattern, its referred to as “spider-web”. “Persian” (Iranian) turquoise is a pure robin’s egg blue without matrix and “American” turquoise varies from pale blue to deep greenish blue to green, most commonly with matrix depending on its source. Special care is required for turquoise due to its porous nature as it can absorb anything that comes in contact with its surface. Turquoise is the original birthstone for December and is designated for the 11th wedding anniversary.