313964d8_Microscopy__Determinative_value
[Optical property] Interference figure [Measurement] Viewed in convergent light between crossed polars with objective of high numerical aperture using a Bertrand lens or pinhole. [Determinative value] 
Aid in determining the optical character of crystals as uniaxial or biaxial. Provides optical orientation of crystals without diagnostic external morphology.
Microscopy
Determinative value