Formica 1

"ant," late 14c., pisse-mire (early 14c. as a surname, Henricus pessemere), from pyss "urine" (said to be in reference to the acrid smell of an anthill) + mire "an ant" (mid-13c., early 13c. as a surname), perhaps from an unattested Old English word or from Old Norse maurr "ant" (cognate with Swedish myra, Danish myre, Middle Dutch miere, Dutch mier, Crimean Gothic miera "ant"), from PIE *morwi- (see Formica (2)). Compare pissant, also Old Frisian pis-imme, Norwegian migemaur (first element from Latin mingere); early Dutch mierseycke (with seycke "urine"), Finnish kusiainen (with kusi "urine").

He is as angry as a pissemyre,

Though þat he haue al that he kan desire.

[Chaucer]

Applied contemptuously to persons from 1560s.

type of mineral that can be separated easily into extremely thin, tough laminae, 1706, from a Modern Latin specialized use of Latin mica "crumb, bit, morsel, grain."  This is sometimes said to be from the same source as Attic Greek mikros "small" (see micro-). The word was applied to the mineral probably on the supposition that it was related to Latin micare "to flash, glitter" (see micacious). However a recent theory of the origin of the Latin noun does derive it from the same root as micare, on the notion of "a glittering crystalline particle" (originally a grain of salt), which de Vaan finds "formally more attractive" than the connection to the Greek word. Older native names for it were glimmer and cat-silver. Related: Micaceous "containing mica" (1748).