Crystals In-Depth provides detailed information on specific crystals and stones.  

Crystals are Mother Earth's gifts to us, formed within Her body, they are living energy, in a way they are the keys to the Universe. Each particular type of crystal or mineral can be seen as a key, and we can use these keys to access specific energies, whether that be for healing, meditation, protection, understanding, as well as a thousand other uses. Crystals have been mined and used for thousand of years, and can be seen in ancient crowns, regalia and jewellery.

For less detail and a wider variety of crystals and stones to review see Crystal Savvy!