• The month of May that includes the zodiac signs of Taurus and Gemini has an assortment of 15 stones listed as birthstones.
• The birthstones marked for May are emerald, sapphire, agate, and carnelian.
• The zodiac signs add on eleven more birthstones: coral, turquoise, aventurine, garnet, amber, rose quartz, tiger's eye, chrysoprase, citrine, white sapphire, and pearl.

Emeralds belong to beryl mineral family with chromium which is responsible for its green coloration. The name emerald comes from the Greek 'smaragdos' via the Old French 'esmeralde', and really just means 'green gemstone'. Emeralds have tiny inclusions resembling green foliage, which the French called "jardin". Some high quality emeralds may be as or even more expensive than diamonds.

The Emerald is a member of the beryl family of minerals. Its chemical formula is Be₃Al₂ (SiO₃)₆. The green crystals grow slowly within metamorphic rocks and are restricted in size by the rock, making large Emeralds rare and costly. Emerald hardness ranges from 7.5 to 8 on the Mohs scale. Even though emeralds are relatively hard stones but due to little inclusions an cracks in emeralds can affect their durability. Emeralds occur in hues ranging from yellowish green to bluish green. The primary hue must, of course, be green.

It took Spanish conquistadors twenty years before they could locate first hige emerald mining by the Muzo Indians, and another thirty years to overtake this aggressive tribe. The Muzo mine was in the area known today as Colombia. Colombian emeralds are among the world's most beautiful, with rich grass-green coloring that's often kissed with a touch of blue. Quality emeralds are also found in India, South Africa, Afghanistan, Pakistan, Russia, and Zimbabwe. Recent finds in North Carolina may provide us with quality emeralds if the mine continues to produce stones. Other countries where this gemstone is found include Australia, Austria, brazil, Bulgaria, Canada, China, Egypt, Ethiopia, France, Germany, Italy, Kazakhstan, Madagascar, Namibia, Nigeria, Norway, Pakistan, Spain and Switzerland.

• The Romans thought emeralds were symbols of fertility and rebirth, and associated the jewel with Venus, the goddess of love and beauty.
• It was Cleopatra's favorite gemstone and she claimed ownership of all emerald mines. She liked to adorn herself with large precious emeralds and gifted emerald gems with her picture engraved to important guests.
• In the sixteenth century, the Spanish Conquistadors were bedazzled by the beautiful emeralds worn by native people. It is often cited as a reason for the Spanish to commit gruesome savagery to get the secret of these emerald mines. It is after a long war and persecution that the Spaniards were able to find and conquer these mines.
• Written many centuries ago, the Vedas, the holy scriptures of the Indians talk of the precious green gems and their healing properties.
• In ancient Rome, green was the colour of Venus, the goddess of beauty and love. And today, this colour still occupies a special position in many cultures and religions. Green, for example, is the holy colour of Islam. Many of the states of the Arab League have green in their flags as a symbol of the unity of their faith.
"Emerald Isle".
• The Wonderful Wizard of Oz the city where the wizard rules is made of emerald thus being called Emerald City, the sixth book in the series is also called after it.
• According to an old legend the Roman emperor Nero wore spectacles made of emerald when he watched the bloody games in his arena. This will not sound all that strange when one knows that one of the first spectacles made had beryl lenses.
• In ancient Egypt, it was considered as a symbol of rebirth and fertility. The dead were buried with an emerald necklace in their neck to ensure eternal life and youth.
• Losing an emerald was considered an omen of evil. This has been proved true by King George III of England. During his coronation, one stone fell from his crown and he soon went insane.

• It is given to commemorate the 20th and 35th wedding anniversary and in some cultures also the 55th wedding anniversary.
• Some people believe that wearing an Emerald brings wisdom, growth, and patience. And as any couple in a long-term relationship would agree, all of these qualities are essential for a successful and lasting love.
• The green of the emerald is the color of life and of the springtime, which comes round again and again. But it has also, for centuries, been the color of beauty and of constant love.
• In China, this gemstone is passed on from mother to the daughter as it is known to ease the pain of childbirth
• It is known for helping in relieving nightmare and insomnia along with treating schizophrenia.
• It is also known for strengthening the immune system and the circulatory system.
• It promotes mental development and stimulates the wearer's intuition.
• It is known for its magic when one wants to attract love, wealth and success.

Carnelian, reddish brown gemstone is known as another birthstone for people born in the month of May. The word carnelian is derived from the Latin word caro, carnis meaning flesh, in reference to the flesh color it sometimes exhibits. Carnelian is a form of chalcedony, a member of the quartz family. It is a semiprecious gemstone with colors ranging from pale orange to an intense almost-black coloration. Carnelian was recovered from Bronze Age Minoan layers at Knossos on Crete in a form that demonstrated its use in decorative arts dating back to 1800 B.C. It is used for treating infertility and to enhance passion.