Mica Aspect Ratios Measured by Scanning White Light Interference Microscopy
Microscopy and Microanalysis
Platy minerals are utilized for their high aspect ratios (average plate diameter divided by plate thickness) in cosmetic, automotive, electronic, and construction applications. Conventional methods of measuring mineral aspect ratios include shadowing  and high tilt observation in the scanning electron microscope (SEM)  . For platy particles that are thin enough to be electron transparent, aspect ratio can be measured through automated measurement of particle diameter combined with
... mbined with measurement of scattering loss for measurement of particle thickness . We previously reported the measurement of the aspect ratio of commercial talc particles (20 to 50 µm average diameter) using scanning white light interference microscopy (SWLIM)  . Comparison with aspect ratios measured using the high tilt SEM observation method showed good agreement. Here we report the results of an attempt to extend the SWILM method to smaller particles utilizing a commercial mica with average diameters < 10 µm.