noun
scintilla
sin-TIL-uh/sɪnˈtɪlə/
A tiny trace or barely detectable amount.
A scintilla of gold shines within the large dark stone.

Etymology
Latin scintilla meant a spark or glittering speck. That minute particle of fire supplied the figurative image for the smallest trace or barely detectable amount of anything.
More examples
- She holds on to a scintilla of hope.
- He agrees without a scintilla of doubt.
- A scintilla of humor lightens the otherwise serious speech.
Forms
scintilla · scintillas · scintillae