When shopping for jewelry or jewelry supplies, it is often difficult to differentiate between glass beads and plastic beads. You can identify a bead's substance with a few simple tests.
Check the Bead's Temperature
Glass beads are cooler to the touch than plastic ones. Pick up the bead in question. If it feels cool in your hand, it is most likely glass. If it feels closer to room temperature or if it warms up quickly in your hand, it is probably plastic.
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If you need to check the same bead's temperature more than once, allow the bead to rest untouched so that it returns to room temperature before you pick it up again.
Weigh the Bead
Plastic is lighter than glass. If you have a jewelry scale, weigh the bead in question and compare it to both glass and plastic beads of a similar size.
If you do not own a jewelry scale, compare the weight of the bead in one hand with the weight of a similarly-sized glass or plastic bead in the opposite hand. If any two feel similarly weighted, then they are probably made of the same substance.
Tap the Bead
If you have extra beads and don't mind possibly sacrificing one, take a bead and tap it lightly with a hammer. If it cracks or breaks, it is glass. If it does not, it is plastic.
Examine the Drilling
If your beads have holes drilled into them, the finish of the holes can help you identify their substance. The holes of glass beads may have a powdery look, while plastic beads appear untouched.
Transparent glass beads may look frosty around the area where the hole was drilled; plastic beads will not have this quality.
Heat the Bead
A plastic bead will melt if enough heat is applied. Use this test on the bead in question to find out if it is plastic.
Things You'll Need
Safety pin or sewing pin
While wearing the heat-resistant gloves, use the lighter to heat the end of a pin until it becomes red in color.
Immediately pierce the bead in question with the pin in an inconspicuous area. If the pin melts the area of the bead where you pricked it, then the bead is plastic.