The Collaborative International Dictionary
Petrographic
Petrographic \Pet`ro*graph"ic\, Petrographical \Pet`ro*graph"ic*al\, a. Pertaining to petrography.
Wiktionary
petrographic
a. 1 Relating to petrographs. 2 Relating to petrography.
Usage examples of "petrographic".
These metamorphic phenomena, though important, are obscure, and their elucidation demands some knowledge of petrographic science, that branch of geology which considers the principles of rock formation.