Where does “microgabbro” come from?

microgabbro (English) comes from English gabbro, from Italian gabbro, from Latin glaber, from Proto-Italic ɣlaðros, from Proto-Indo-European gʰleh₂dʰ-ro-s, from Proto-Indo-European gʰleh₂dʰ- — bright, shining; smooth.

microgabbro (English): A fine-grained igneous rock with the same composition as gabbro but having an ophitic texture; diabase

Definitions

A fine-grained igneous rock with the same composition as gabbro but having an ophitic texture; diabase

Ancestry of “microgabbro”, step by step

microgabbro traces back through two separate lines of ancestry.

via English gabbro

Step	Language	Word	Meaning
1	English	gabbro	Originally, a kind of serpentine; now generally a...
2	Italian	gabbro	gabbro
3	Latin	glaber	smooth; hairless
4	Proto-Italic	ɣlaðros	smooth
5	Proto-Indo-European	gʰleh₂dʰ-ro-s	—
6	Proto-Indo-European	gʰleh₂dʰ-	bright, shining; smooth

via English micro

Step	Language	Word	Meaning
1	English	micro	Small, relatively small; short form of...
2	Ancient Greek	μικρός	little, small
3	Proto-Indo-European	mēy-	soft, tender, dear

Words derived from “microgabbro”

microgabbroic

Every word from Proto-Indo-European gʰleh₂dʰ- →Every word from Proto-Indo-European gʰleh₂dʰ-ro-s →Every word from Proto-Italic ɣlaðros →