Here is a quartz crystal model meant to be a teaching aid. One version is labeled and the faces identified. A second version lacks labels and has faces large enough so that the interfacial angles can be measured with a simple protractor. A brief description of the model and how to use it is in Angles.txt. OpenSCAD code is included.
Inexpensive protractors can be purchased from building supply stores like The Home Depot or Lowes. Results accurate to plus or minus a degree are easily obtained.