Chalcedony

Chalcedony and its named varieties are well represented in various birthstone charts and can be found for all the months except January, April, and November. It is also listed as a birthstone for all the Zodiac signs except Taurus, Cancer, Scorpio and Sagittarius.
The term chalcedony is derived from the name of the ancient Greek town Chalkedon in Asia Minor.
Chalcedony, which is found worldwide, is the name for a group of stones made of a microcrystalline or cryptocrystalline variety of quartz, which means the quartz crystals are too small to be seen without high magnification.
In jewelry usage, the name Chalcedony is usually applied only to the light blue translucent and waxy form. Other stones in this group are know as agate, jasper, petrified wood, bloodstone, petrified dinosaur bone, fire agate, tiger's eye, chrysocolla, chrysoprase, onyx, sardonyx, and carnelian.

Chalcedony is found in almost every color including: white, gray, black, brown, brownish red, orange, yellow, light to dark green, blue, lavender or, in the case of agates and jaspers, combinations of those colors.

Folklore, Legend, and Healing Properties:
Native American Indians believed chalcedony was a sacred stone and used in the spiritual ceremonies of the tribe.

It is thought to increase vitality, stamina, and endurance and to promote emotional balance and charity while relieving melancholy, fever, gallstones, and eye problems.