A gem associated with the month of birth. Over the ages and in different countries there have been many versions of birthstones. In order to make preparation and advertising of birthstones easier for jewelers, in 1912 a professional organization, the Jewelers of America, announced a list that has become the most popular in the U.S. and other countries. The list is:

January: Garnet
February: Amethyst
March: Aquamarine
April: Diamond
May: Emerald
June: Moonstone (or Pearl)
July: Ruby
August: Peridot
September: Sapphire
October: Opal (or Tourmaline)
November: Yellow Topaz (or Citrine)
December: Turquoise (or Blue Topaz, and as of 2002, Tanzanite)