They seem to have grown rapidly, as they are often filled with enclosures of glassy or finely crystalline material like that of the ground-mass.

It thus enables the direct viewing of columns of atoms in a crystalline material.

There are other vacuoles that may contain membranous inclusions, while still others contain crystalline material variously interpreted as oxalate crystals or crystalline uric acid.

This means a crystalline material can deform under a differential stress, by the flow of vacancies.

On electron microscopy the mineral deposits appear as amorphous or crystalline material surrounded by a basal membrane.