This is a small pile of powdered frog, about one pinch.
"look powder" will give you a rough estimate of how many handfuls you have, rounded to the nearest full number. If under a handful, it'll give you an estimate of how many pinches you have. "count powder" will give you the exact number of pinches you have, up until one handful, after which it also rounds up to the nearest full number of handfuls.
Thus, 1 handful and 24 pinches will "look" and "count" like one handful, but 1 handful and 25 pinches will "look" and "count" like two handfuls.
The correct way of testing if you have over x handfuls is to do "count x handfuls of powder". This will let you know if you actually have that many handfuls.
You can "put x handfuls of powder in container" and "palm x handfuls of powder from container" but using "get powder" will only take at most one handful at a time.
Stacklady's Morphic Resonator, one pinch.
Where to get some
Ankh-Morpork Apothecary on Prouts (costs 5p)
A small dingy shop on the east section of The Serpent, Bes Pelargic (costs 5s)