The promise of mental clarity is such a luxury in a society already crowded with digital, emotional, and even existential noise. Here come gemstones, which are ancient, attractive, and marketed as aids for cognitive harmonization as well as a way to focus and relax. Gemstones and mental clarity often go hand in hand in such narratives—a stone may be a quest for positive and clear thinking, whether it's amethyst with its purported stress-reduction properties or emerald stone and its reputation as the stone of communication and clarity. But how mythical is brilliant light, or how scientific is all this?