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. Emeralds are a variety of the mineral beryl (Be3Al2(SiO3)6,) colored green by trace amounts of chromium and sometimes vanadium. Beryl has a hardness of 7.5 - 8 on the 10 point Mohs scale of mineral hardness. Most emeralds are highly included, so their brittleness (resistance to breakage) is classified as generally poor. The word "emerald" comes from Latin smaragdus, via Greek smaragdos, its original source being a Semitic word or the Sanskrit word, marakata, meaning "emerald" or "green".