There are lots of different colored and sizes of rhinestones available, perhaps that is the term you are thinking of. Rhinestone supplies also usually carry other forms of heat transfer objects. Generally Rhinestones are applied with a heat press and using a template, the template can either be computer cut, or made via drawing software and the stones placed by hand.
For more information, I suggest checking out the rhinestone forums here and reading through some of Sandyjo's (sjidohair) posts and tutorials:
Rhinestone Decoration - T-Shirt Forums