Gemstone nuggets, chips and pebble beads from Rings & Things:
A nugget is an irregular bead with no definite shape. Usually larger than a chip, this shape is sometimes also known as a knucklebone or macadam.
The fun gemstone chips from the 80's are not so common any more. Every now and then, we run across some that are worth buying, but most gemstone chips we see on the market now are poorly dyed stones that mimic more costly stones -- be warned that those chips often leak dye all over clothing the first few times they are worn. (We avoid stocking those.)
Gemstone pebbles are irregularly-shaped beads, but smooth and rounded, not as rough as nuggets or chips. They provide a great free-form texture for beaded jewelry designs.