Birthstones
There is at least one birthstone for each month, and for some months there are more.  For example, December has four and June  has three while March, April, August, October, and November have two.


January        Garnet
February      Amethyst 
March          Bloodstone or Aquamarine
April            Diamond or Black Star Sapphire
May             Emerald
June             Pearl, Moonstone, or Alexandrite
July              Ruby
August         Peridot or Sardonyx
September   Sapphire
October       Opal or Tourmaline
November   Topaz or Citrine
December   Turquoise, Tanzanite, Zircon, or Lapis