sponge
small pieces of coal are called slack. Thank you!
Small pieces of colored glass are called "mosaic tiles."
they are called florets
ATOMS
Small pieces of gold are called gold nuggets. These are nuggets can be found in rivers, streams, or underground and vary in size.
Chyme
The small ones are called 'Netsuke'.
organelles
Small leftover pieces of cigarette are called cigarette butts.
Mosaics.
A small narrow waterway between two pieces of land is called a strait.
Making (cutting) those small irregular pieces might be called dicing, and the bits are said to be diced.