August has two birthstones, Peridot, a variety of olivine, and Sardonyx, a form of chalcedony.
Peridot is a transparent gem form of olivine. It is composed mostly of magnesium and iron silicates. Colour ranges from olive to lime green.  The shade of green is caused by iron and sometimes the gem has a brown tinge if the iron content is especially high.

 
   Since ancient times peridot has been associated with the Sun, and believed to bring great dignity to anyone who wore it. During the Middle Ages, peridot was worn around the left arm to ward off evil spirits.

     Some very pretty green peridot gems are called evening emeralds and have been treasured over the ages. The crusaders thought they actually were emeralds and brought them back to be used as church ornaments.

     One of the oldest and best sources for exceptional peridot crystals is the island of Zabargad, in the Red Sea, mined since ancient times for peridot. The name Zabargad  means olovine in Arabic. But it is not a nice place: no vegetation, scorching heat except in the dead of winter and there is no fresh water source.  But whatever the island lacks in comfort, it makes up for in peridot. Whole fissures are lined with peridot crystals, some several centimeters long! The beaches of this island have a greenish hue from the tiny peridot crystals in the sand.

     Peridot can also be found to smaller degrees in Burma, Norway, China, Australia and Mexico. Peridot has also been found in a few meteorites.

     Peridot is among the oldest known gemstones. The "topaz" on the breastplate of Aaron,High 
Priest of the Hebrews in the Old Testament, was believed to actually be peridot. Ancient Egyptians, around 1580 B.C. to 1350 B.C., created beads from peridot.  The Greeks and Romans also liked peridot jewelry. Perhaps the largest peridot collection was collected by the Ottoman empire.

     The second birthstone for August is Sardonyx. This mineral has a banded appearance because it is constructed by tiny layers which are stacked on top of each other. The bands vary in colour from translucent to opaque. The stone itself varies in colour from white  to gray along with a few coloured shades. The most common Sardonyx  contain flat-banded, white and brownish-red bands. The name Sardonyx comes from the Greek word Sard "reddish brown." and  Onyx "veined gem."
 

    The best samples of Sardonyx are found in India, but they can  also be found in Germany, Czechoslovakia, Brazil, and Uruguay. In the United States, sardonyx can be found in the Lake Superior region and in Oregon.

     A very common use for Sardonyx was to use it for carving cameos. The coloured layer is the background and the white part of the stone is used as relief. Roman soldiers would carve heroes such as Hercules or Mars in the stones and wear them with the belief that the stone would make them as brave as the figure carved in the stone.  In later times the stone was though to bring elegance to it's wearer and was of value to public speakers.
 
     It is odd that Sardonyx has always been so popular because it is quite common and never had any high value such as other gemstones. Perhaps it was just because it is such an attractive stone that made it so popular. Whatever the reason, Sardonyx was worn both by rich and not so rich.
A well known story about Sardonyx centers around Queen Elizabeth. She had a beautiful stone set in a gold ring and had her portrait carved on the stone. She presented the ring to the Earl of Essex as a token of friendship, assuring him that if he ever asked for help, she would be there. Later, the Earl was imprisoned for treason and condemned to die. The Earl tried to send the ring to the Queen to ask for her aid, but instead it landed in the possession of Lady Nottingham,  an enemy of the Earl. Queen Elizabeth learned of his plight, but since he did not ask for her aid, she assumed he was to proud and so she did nothing. The Earl was beheaded. It was not until a deathbed confession by the Lady of Nottingham that the Queen learned the truth. It broke her heart.