QUARTZ OR GLASS?
To tell whether a vessel is made of quartz or glass, a researcher can place the vessel between a fluorescent object, such as a TLC plate (at top in photo), and a shortwave UV light (at bottom in photo). Quartz vials, which are must-haves for certain photochemical experiments, transmit the light (left and right), but a glass beaker absorbs it, casting a shadow (center).
Credit: centralscience.tumblr.com