Small, parallel grooves (twinning striations)are visible on cleavage surfaces and characteristic of which mineral?
A)olivine
B)quartz
C)plagioclase feldspar
D)hornblende

Question

Quizplus · Accepted Answer

Plagioclase feldspar is known to exhibit twin striations on its cleavage surfaces, which are parallel grooves that are the result of twinning during crystal formation. Olivine, quartz, and hornblende do not typically show twinning striations on cleavage surfaces.

Small, Parallel Grooves (Twinning Striations)are Visible on Cleavage Surfaces and Characteristic