Crack propagation & crack length?

Hi all, I am new here and I have a question.  I have this hydroxyapatite material which is 60% porous and it is very brittle.  I got the material cut already and i was wondering when using SEM, is it possible to use the SEM to measure the crack length?  I am just wondering as to what the use of SEM is besides studying the pore size and to see if any cracks appear before and after cutting the material.  Is it still possible to find the crack propagation even though loading tests were not carried out on the material?  Can you suggest any reading materials on crack length n propagation?  Thanks!