Where does “mica” come from?

mica (Latin) comes from Proto-Italic smīkā, from Proto-Indo-European smēyg-, from Proto-Indo-European smē- — to rub; smear.

Ancestry of “mica”, step by step

Step	Language	Word	Meaning
1	Proto-Italic	smīkā	—
2	Proto-Indo-European	smēyg-	small, delicate, thin; twig, pole; crumb; small,...
3	Proto-Indo-European	smē-	to rub; smear

mica — Etymology, Origin & Word History | Etymology Explorer