When most people think of Rosmarinus officinalis  (now classified botanically as Salvia rosmarinus ), culinary uses often come to mind—roasted vegetables, hearty stews, or a fragrant addition to home-cooked meals. While rosemary is indeed a beloved culinary herb, it also yields a distinctive essential oil that is widely used in both aromatherapy and cosmetic formulation. One of the most interesting aspects of rosemary essential oil is that it exists in several chemotypes. A c

The Chemistry Behind Aroma Chemistry was one of my favorite subjects in high school. Beyond the elegance and logic of the periodic table, I was especially drawn to time spent in the laboratory—observing reactions, color changes, temperature shifts, and the formation of precipitates (something far less desirable in cosmetic formulations today, but endlessly fascinating at the time). My husband, who is also a scientist, has a vivid memory from his own high school A.P. chemistry