Earth (element)
Earth is one of the classical elements, in some systems being one of the four along with air, fire, and water.
Earth is one of the five elements that appear in most Wiccan and Pagan traditions. Wicca in particular was influenced by the Golden Dawn system of magic, and Aleister Crowley's mysticism which was in turn inspired by the Golden Dawn.
Alchemy
In alchemy, earth was believed to be primarily dry, and secondarily cold. Beyond those classical attributes, the chemical substance salt, was associated with earth and its alchemical symbol was a downward-pointing triangle, bisected by a horizontal line.
Golden Dawn
Earth and the other Greek classical elements were incorporated into the Golden Dawn system of ritual magic. Zelator is the elemental grade attributed to earth; this grade is also attributed to the Qabbalistic sphere Malkuth. The elemental weapon of earth is the Pentacle. Each of the elements has several associated spiritual beings. The archangel of earth is Archangel Uriel, the angel is Phorlakh, the ruler is Kerub, the king is Ghob, and the earth elementals (following Paracelsus) are called gnomes. Earth is considered to be passive; it is represented by the symbol for Taurus, and it is referred to the lower left point of the pentagram in the Supreme Invoking Ritual of the Pentagram. Many of these associations have since spread throughout the occult community.