About Birthstones Nov 30, 2018 | Birthstones, From The Experts Birthstones by Month In 1912, the American National Association of Jewelers agreed on the birthstone chart that we use today. January: Garnet February: Amethyst March: Aquamarine April: Diamond May: Emerald June: Pearl or Alexandrite July: Ruby August: Peridot September: Sapphire October: Opal or Pink Tourmaline November: Citrine or Topaz December: Blue Zircon or Blue Topaz