What is a Chalk crystalline or amporphous? and why?
In condensed matter physics, an amorphous (from the Greek a, without, morph�i> , shape, form) or non-crystalline solid is a solid that lacks the long-range order characteristic of a crystal.
In part of the older literature, the term has been used synonymously with glass . Nowadays, "amorphous solid" is considered to be the overarching concept, and "glass" the more special case: A glass is an amorphous solid that transforms into a liquid upon heating through the glass transition. 
Other types of amorphous solids include gels, thin films, and nanostructured materials
|Amorphous forms of silica||Crystalline forms of silica|