Birthstone Guide
Most gem scholars agree that the tradition of birthstones arose from the Breastplate of Aaron: a ceremonial religious garment set with twelve gemstones that represented the twelve tribes of Israel and also corresponded with the twelve signs of the zodiac and the twelve months of the year.

Because ancient civilizations did not always classify gemstones by mineral species like modern day gemologists do, there is some debate about which gemstones were set in the breastplate and why. Because of this, different cultures around the world have developed different birth stone lists. The modern day list that you know is only the most recent list; some older lists still exist.

Some also argue that the proper way to assign gemstones is according to astrological sign and not month. There are also those that think it is more fun to choose the gemstone that speaks to you from all the possibilities.
Birthstone Guide January
Modern Birthstone: Garnet

Gemstone for Capricorn: Ruby

Ancient traditional birthstones
Hebrew: Garnet
Roman: Garnet
Arabic: Garnet
Hindu: Serpent-stone
Polish: Garnet
Guardian Angel: Gabriel
His Talismanic Stone: Onyx
 		  Birthstone Guide February
Modern Birthstone: Amethyst

Gemstone for Capricorn: Garnet

Ancient traditional birthstones
Hebrew: Amethyst
Roman: Amethyst
Arabic: Amethyst
Hindu: Chandrakankta
Polish: Amethyst
Guardian Angel: Barchiel
His Talismanic Stone: Jasper
Birthstone Guide March
Modern Birthstone: Aquamarine

Gemstone for Capricorn: Amethyst

Ancient traditional birthstones
Hebrew: Bloodstone
Roman: Bloodstone
Arabic: bloodstone
Hindu: Gold-sivalinga
Polish: Bloodstone
Guardian Angel: Malchediel
His Talismanic Stone: Ruby
 		  Birthstone Guide April
Modern Birthstone: Diamond

Gemstone for Capricorn: Bloodstone

Ancient traditional birthstones
Hebrew: Sapphire
Roman: Sapphire
Arabic: Sapphire
Hindu: Diamond
Polish: Diamond
Guardian Angel: Ashmodei
His Talismanic Stone: Topaz
Birthstone Guide May
Modern Birthstone: Emerald

Gemstone for Capricorn: Sapphire

Ancient traditional birthstones
Hebrew: Agate
Roman: Agate
Arabic: Emerald
Hindu: Emerald
Polish: Emerald
Guardian Angel: Amriel
His Talismanic Stone: Carbuncle (Garnet)
 		  Birthstone Guide June
Modern Birthstone: Pearl or Alexandrite

Gemstone for Capricorn: Agate

Ancient traditional birthstones
Hebrew: Emerald
Roman: Emerald
Arabic: Agate
Hindu: Pearl
Polish: Agate
Guardian Angel: Muriel
His Talismanic Stone: Emerald
Birthstone Guide July
Modern Birthstone: Ruby

Gemstone for Capricorn: Emerald

Ancient traditional birthstones
Hebrew: Onyx
Roman: Onyx
Arabic: Carnelian
Hindu: Sapphire
Polish: Ruby
Russian: Ruby
Guardian Angel: Verchiel
His Talismanic Stone: Sapphire
 		  Birthstone Guide August
Modern Birthstone: Peridot

Gemstone for Capricorn: Onyx

Ancient traditional birthstones
Hebrew: Carnelian
Roman: Carnelian
Arabic: Sardonyx
Hindu: Ruby
Polish: Sardonyx
Guardian Angel: Verchiel
His Talismanic Stone: Diamond
Birthstone Guide September
Modern Birthstone: Sapphire

Gemstone for Capricorn: Carnelian

Ancient traditional birthstones
Hebrew: Peridot
Roman: Peridot
Arabic: Peridot
Hindu: Zircon
Polish: Peridot
Guardian Angel: Hamatiel
His Talismanic Stone: Zircon
 		  Birthstone Guide October
Modern Birthstone: Opal or Tourmaline

Gemstone for Capricorn: Peridot

Ancient traditional birthstones
Hebrew: Aquamarine
Roman: Aquamarine
Arabic: Aquamarine
Hindu: Coral
Polish: Aquamarine
Guardian Angel: Tsuriel
His Talismanic Stone: Agate
Birthstone Guide November
Modern Birthstone: Topaz or Citrine

Gemstone for Capricorn: Beryl

Ancient traditional birthstones
Hebrew: Topaz
Roman: Topaz
Arabic: topaz
Hindu: Cats-eye
Polish: Topaz
Guardian Angel: Bariel
His Talismanic Stone: Amethyst
 		  Birthstone Guide December
Modern Birthstone: Tanzanite, Turquoise or Zircon

Gemstone for Capricorn: Topaz

Ancient traditional birthstones
Hebrew: Ruby
Roman: Ruby
Arabic: Ruby
Hindu: Topaz
Polish: Turquoise
Guardian angel: Adnachiel
His Talismanic stone: Beryl