Very cute item sprites, the animations are really fun!
The animations are subtle but work really well, also nice colours!
These are nice! I do feel like the electric one could have some of its arcs overlap the front of the stone, like the purple ones, as they work really well. 
Less is more in frames if you can pull it off, and you have :)
ooh, shiny! i like the glow effect and reflection, nice touch
Lovely!