Ground pieces of glass are called frit.
Frit is used by glass blowers, lampworkers, and kiln-glass artists to decorate glass objects that they create. Glass blowers and lampworkers will often roll a hot gather of glass over frit. Kiln-glass artists use frit as a surface decoration, for casting, and more. The possibilities available with frit are limitless.
Frit is available from many glass manufacturers. Typically (though not always) frit is sifted and sold by mesh size. The finest frits are also call powders.
You can also make your own frit by crushing glass. Common methods include:
- wrapping the glass in newspaper and smashing with a hammer
- a garbage disposal (described in Glass Fusing Book Three by Boyce Lundstrom)
- use a hand-held glass crusher (can be made from steel pipes or purchased)
- heating the glass (typically above 500 F) and then quenching in cold water
If you use any method that relies on metal-against glass, make sure to clean the glass of any metal contaminants. The easiest way to do this is with a strong magnet.