Agate

"She is the fairies midwife, and she comes In shape no bigger than an agate stone On the forefinger of an alderman" William Shakespeare, Romeo and Juliet Act 1, scene 5 Also known as Chalcedony, Agate's many subspecies are distinguished by their colors and patterns. Tiny crystals of Quartz interlock to form Agate, which is always opaque to translucent because of this. Some types of Agate are:

Blue Chalcedony: Agate with a blue solid body color. Example, Ellensburg Blue

Carnelian: Yellow-orange to orangey red, translucent. Credited with turning away the evil eye, strengthening the spirit, and protecting from misfortune. Carnelian was also thought to give courage to the timid, banish sadness, encourage friendships and bring contentment.
Chrysocolla: Intense light blue or blue-green Agate containing the mineral Chrysocolla.
Chrysoprase: Light to medium yellowish green, translucent. Was once considered to be a prized form of Jade.
Drusy: Agate cut with the natural surface of tiny crystals retained (see at Left.)
Bloodstone: Dark green with dark red spots, opaque. Legends say that Bloodstone was formed from drops of Christ's blood as he was crucified. It was thought to have the power to stop bleeding, give wisdom, and protect against enemies.
Blue Lace Agate: Lavender to light blue with lacy white lines, translucent. Supposed to aid in contemplation and meditation.
Fire Agate: Iridescent colors against a brown body color, translucent.
Jasper: Differing opaque colors, usually green red or yellow. Also picture Jasper showing landscape like patterns. Jasper had the attribute of bringing rain to drought ridden lands, and of curing epilepsy and cancer.
Moss Agate: Brown or green inclusions that look like moss or leaves, translucent. A helpful talisman for the gardener, to ensure that plants would grow healthy and strong.
Onyx or Sardonyx: Banded or solid color opaque Agate. Offered protection from the evil eye and empowered the mind and spirit. Also reputed to bring sexual bliss, and monetary success to its owner, if it was worn at all times by its owner.
Petrified Wood: Wood that has been replaced by Agate which follows the wood's structure. Agate in general was thought to protect and give courage to its wearer, and to help against bad dreams and insomnia. Some sources credit Agate with preventing skin ailments and cooling fevers. It is known in the Middle East that an Agate pebble held in the mouth will relieve thirst. Hardness: 6.5-7 Toughness: Good