Yggdrasil, the tree of life (Norse mythology). Its many roots and limbs keep all the different worlds together: Asgard, Midgard, Helheim, Niflheim, Muspellheim, Svartalfheim, Alfheim, Vanaheim and Jotunheim. Below its roots there is the spring that fills Mimisbrunnr, the well of wisdom, guarded by Mimir.
Amethyst. It is a mineral of hydrothermal and magmatic origin. It is formed in iron oxide rich veins, which give it its characteristic purple at temperatures below 300 Celsius degrees. Usually the amethyst is found covering the inside of agate geodes. It can also be found as a druse (crystals lining the surface of a stone) or in veins, accompanied by other minerals. The name amethyst comes from the Greek amethystos (not drunk), as this stone was considered a powerful antidote against drunkenness. According to Greek mythology, Dionysus, god of wine and excess, wooed a maiden named Amethystos, who wished to remain chaste. The goddess Artemis heard his prayers, and transformed the woman in a white rock. Dionysus, humiliated, poured wine on the rock as an apology, dying the crystals purple. Amethyst has been known for thousands of years. In ancient Egypt was used in jewelry, personal seals and other goods. In the Middle Ages, Christianity adopted Amethyst as symbol of renunciation of worldly goods, and chastity. Amethyst also symbolizes divine wisdom. Amethyst is a crystal of the quartz family, so it has its powers, especially the capacity to polarize the positive energy. Also it is considered the balance stone in the physical, mental and spiritual world. Amethyst provides energy, balance and spirituality.