Orb pieces look like this:
Orb pieces can be traded towards customs, breedings, and many other things. You can use as many or as few orb pieces at a time. If you're applying it for a custom or breeding make sure that the artist accepts orb pieces ahead of time.
In the second post is a list of names and how many orb pieces.
Orb Trade-ins
5 Orb Pieces Pre-made Familiar
10 Orb Pieces: Several Color and Design Option Familiar
15 Orb Pieces: Full Custom Familiar
20 Orb Pieces: Cosplay Familiar
25 Orb Pieces: Breedings - + 1 guaranteed soul gem (so now starting roll will be at 2)
30 Orb Pieces: Breedings - + 2 guaranteed soul gems (so now you're guaranteed 3 soul gems)
35 Orb Pieces: Pre-made Custom
40 Orb Pieces: Several Color and Design Options Custom
45 Orb Pieces: Full Custom
50 Orb Pieces: Cosplay Custom