Geologic: Apatite is a general term for a group of phosphate minerals with similar chemistry that can form in a myriad of conditions. It is most often blue, green or yellow and is sometimes found as hexagonal crystals with brilliant color and transparency that can be made into gemstones.
Chemical composition: Ca5(PO4)3(Cl/F/OH); Hardness: 5
Metaphysical: "Can be used to stimulate the intellect and to promote realization that ones strength occurs through both spiritual avenues and via love; hence, dissolving aloofness and negativity." - Melody