need value of missing smd capacitor

[Luddite]

A really small one got away but I got a good look at it.
square ends with a white ceramic looking body and a small
blue square on one side,probably in the low pf range

 

[Craig Hart]

Parts like that are available in at least 5 orders of magnitude - so
guesswork probably won't help.

consider consulting the schematic for component value.