The History of birthstones is believed to have gone back to the book of Exodus with the Breastplate of Aaron. It was a garment with twelve gemstones sewn into it that represented the twelve tribes of Israel. The gemstones were set in three rows of three gemstones. At that time the gemstones were “sardius, topaz and carbuncle; emerald, sapphire and diamond; ligure, agate and amethyst; beryl, onyx and jasper.
The connection between the Breastplate of Aaron and the twelve stones of the zodiac were written about by Favius Josephus (1st century A.D) and St. Jerome (5th century A.D.). It was believed that wearing the gemstone of your zodiac would bring good luck to the wearer and that the stone had special powers.
Scholars from the 18th century in Poland came up with the modern ideas of a birthstone for each month. The most well-known list of monthly birthstones came into being in 1912 by the National Association of Jewelers in the United States.
Since 1912, the monthly birthstones have remained the same until 2002 when tanzanite was added as the birthstone for December. December also has three birthstones designated for this month.
The current list of monthly gemstones is as follows:
January Garnet (dark red)
February Amethyst (purple)
March Aquamarine (pastel blue)
May Emerald (green)
June Pearl or Alexandrite (the color changing stone)
July Ruby (red)
August Peridot (light green)
September Sapphire (blue)
October Opal or pink tourmaline
November Citrine (yellow orange), yellow topaz
December Blue zircon, blue topaz, turquoise or tanzanite (bluish