Stone Elemental Ruler
Earth: Stones related to this element are useful in promoting peace, grounding, and centering of energies, fertility, money, business success, stability, gardening, and agriculture. Candles used in conjunction with these stones should be green.
Air is the element of communication, travel, and the intellect. Its color is yellow.
Fire stones are used for protection, defensive magic, magical energy, physical strength, will power (such as in dieting), and purification. Candle color is red.
Stones of water are used in love rituals, and for healing, compassion, reconciliation, friendship, purification, de-stressing, peace, sleep, dreams, and psychism.
Agate, Blue lace
Akasha is the fifth element, and its stones are usually of organic origin, either substances from living creatures of fossils of long deceased animals and plants. The are useful in a variety of magical applications, including longevity and past-life regression.
Cunningham's Encyclopedia of Crystal, Gem, and Metal Magic