tags: #publish links: [[Gemstone Faceting]] created: 2022-01-06 Thu --- # Immersion fluids and refractive idexes https://www.gemsociety.org/article/gemstones-refraction-liquids/ https://www.gemsociety.org/article/refractive-index-list-of-common-household-liquids/ https://usfacetersguild.org/forums/topic/is-refractol-still-available/ Immersing in a fluid close to the refractive index of a piece of gem rough allows "seeing inside" despite the rough surface. Unfortunately most very high RI liquids are dangerous toxic substances. "Refractol" product is no longer produced. Several vegetable oils are reasonable substitutes. Glycerine (glycerol) is higher RI than water. Some folks have even had success with hand sanitiser which is essentially water, alcohol and glycerine.