The colorless, transparent variety of quartz. Quartz is composed of silicon dioxide, the most common mineral in Earth’s crust after ice and feldspar. The name “rock crystal” emerged in the Middle Ages to differentiate it from colorless glass. The Greeks called water-color crystals krystalos, hence the name “crystal.” The name quartz comes from Old German, but its origins are unknown. Metaphysically, quartz is used for power, communication, and cleansing. Found worldwide, fine specimens of quartz can be found in Arkansas, Brazil, and Madagascar.
Tourmaline is a crystal silicate mineral with the broadest color palette of any mineral group. The name derives from the Sinhalese turmali, meaning many-colored gems. Bi-colored and multicolored crystals are common, reflecting variations of fluid chemistry during crystallization. Each color has its own mineral name, including rubellite (red, pink), indicolite (blue), dravite (brown), and schorl (black). Tourmaline is found in Sri Lanka, Brazil, and California. Metaphysically, each color of tourmaline has a specific attribute: schorl is good for protection, rubellite applies to matters of the heart, and indicolite aids with intuition.