Glass Vs. Plastic.

Q: I have been making polymer clay beads and jewelry for about five years now, and I never used to worry to much about what my "filler" beads were made of in my jewelry, but now, I'd prefer to use glass seed beads instead of plastic ones. Okay, no problem - buy nice ones from now on. BUT I have a big jumble of beads that I'm not sure what they're made of, and they're so little - how can you tell?

A: I took some glass seeds and put them in water. All of them (100%) sank. I took some plastic 2mm pearls and put them in water. About 90% floated. Even if not ALL the plastic ones float, you can be sure the ones that DO float are plastic (omg, this sounds like one of those tricky logic questions - if some plastic beads float, are floating beads plastic?). 1. By weight. Glass beads are heavier than plastic beads. Go to a bead store and ask to see glass and plastic beads and then take a bunch of each (same size) in your hands and feel the weight. After a while, you just get an instinct. 2. By breaking open one bead with pliers and looking at the pieces to see if it broke like glass. 3. Plastic beads will often have a line around them where the top of the mold met the bottom of the mold. Look for the line.