These faceted glass beads are cut, then tumbled to produce a smoother surface, making them more comfortable to wear than some cut glass shapes. They also have generous sized threading holes.
The classic 'granny' necklaces that your great grandmother may have left you might be made from these!
The different sizes lend themselves to many different applications, but probably the 4mm size is the most used - weavers of designs especially use this size, or smaller.
