All glass beads are classified beginning with how they are made—because most of the time the structure of a bead is more-or-less discernible, and differences are distinctive.

A wound bead is formed on a mandrel, from glass that is in a liquid or semi-liquid state, The structure of the resulting bead reflects that. The fabric of the glass can be seen to flow around the (now departed) mandrel. That is the aperture of the perforation. Wound beads have glass flow that follows the circumference of the bead (just as drawn beads have flow that progresses from one end to the other—because they are derived from drawn canes). Many wound glass beads may have bubbles or contaminations that likewise flow with the structure of the glass, around the circumference.

A powderglass bead is composed from glass that has been crushed in a cold hard state. This crushed glass is then used to construct a bead. Often there is a binding medium (that may be as simple as water or saliva). The resulting bead is either formed around a mandrel, or a sharp tool is inserted through it to form a perforation.

Taking a close look, a powderglass bead would never show the flowing fabric or structure of glass of a wound bead. The fabric of a powderglass bead is very distinct. Under magnification, you can actually SEE the granules of glass that make up a powderglass bead. A poked hole is very different from a hole that is created in winding.

Powderglass beads, generally, are not good imitations of wound beads. The reverse is true also. Wound beads are not good copies of powderglass beads.

I hope this is helpful. Jamey