You want to determine the crystal content, but instead you can analyze your powder for elements and then calculate the crystal content. Atomic absorption spectrometry is considered an accurate method. To do this, a certain powder sample must be dissolved in a suitable acid or alkali and analyzed for the content of elements.
XRD can give a very Deep information about the same however, it depends on your analysis capabilities. And if can combine results ofDSC and PXRD then amazing..