Epidote

Chemical Composition: Epidote is a basic calcium, aluminum, iron silicate.

Epidote usually occurs in a dark olive green color, and is often confused with tourmaline. It can be identified by its crystal structure which is different from tourmaline.
Hardness: 6-7

Metaphysical Attributes: Enhances perception and personal power. Excellent for attunement in all aspects of awareness, improvement, abundance, and healing.
Corresponding Astrological Sign: Gemini

All of the specimens below have nice crystal formation and are dark olive green in color.