The Arcane discipline covers any activity that uses knowledge from the scientific disciplines to manifest intended results. The Ritual subdiscipline covers any activity that uses any ritual to manifest intended results. The crystalline subdiscipline covers any object that uses a crystalline nature to change the form of energy in a or complex pattern. Agate (pronounced ['ægət]) is a microcrystalline variety of quartz (silica), chiefly chalcedony, characterised by its fineness of grain and brightness of color. Although agates may be found in various kinds of rock, they are classically associated with volcanic rocks but can be common in certain metamorphic rocks. Colorful agates and other chalcedonies were obtained over 3,000 years ago from the Achates River, now called Dirillo, in Sicily. The stone was given its name by Theophrastus, a Greek philosopher and naturalist, who discovered the stone along the shore line of the river Achates sometime between the 4th and 3rd centuries BC.