Patchouli is a very fragrant herb with soft oval leaves and square stems. It grows from 2 to 3 feet in height and provides an unusual odor that is nonetheless characteristic of patchouli when the leaves are rubbed. It became very popular throughout the British Empire when silks and cashmere shawls from India were packed with Patchouli to discourage insects during shipping, the scent being the final proof of origin. Genuine India Ink was also scented with it. Patchouli improves with age, and the aged oil is what is preferred over that which is freshly harvested. In aromatherapy and perfumery, Patchouli provides an excellent fixative that can help extend other, more expensive oils.