Beads can be made from all kinds of different materials. The good news is that most types of beads are quite easy to tell apart. However, distinguishing between glass beads and those made from semi-precious stones can be more difficult. If you have a large collection of beads that you are trying to sort, or if you want to buy beads or products made with beads and aren't sure what you have in front of you, there are a few things you can do to distinguish between glass and stone.
Ensure that you have adequate lighting. In order to tell beads apart, you need to be able to see them clearly. It is easy to mistake one type of bead for another when buying them in dimly-lit shops, but it is much harder to mistake different types when they are illuminated under a bright lamp.
Test the sounds of beads. Beads that are made out of different materials sound differently when they are rattled against each other. Grab a handful of beads that you know to be glass and shake them. You can then identify other beads by matching the sound. Beads that sound different from the glass beads may be stone.
Inspect the beads visually. Glass beads can be cut in a variety of shapes. Stone beads tend to be smaller in shape and are often left with some of their natural character rather than ground perfectly smooth. Semi-precious stones can also be abnormal in shape if left in their natural state.
Look for texture and grain within the bead. Semi-precious stones tend to have more non-uniform swirls and shapes within them than the average glass bead does. You can also compare the bead to pictures of semi-precious stones to see if they match images of any stones, such as amber or amethyst.
Examine the hole drilled in the bead. Glass beads can sometimes show frost lines from drilling or look like they have powder inside of the hole. A stone bead, on the other hand, may have some faint chipping around or inside the hole.