The setup was created by Alex Martinelli and can be downloaded for free.
Data Scientist and Blender enthusiast Alex Martinelli has released a cool new Geometry Nodes-powered setup that will allow you to create realistic-looking and highly customizable procedural crystals in Blender.
According to the project's description, the Blender file shared by Alex contains the crystal GN node-tree, as well as two procedural materials, one for the surface and the other for the optional volume. Thanks to the large selection of options provided by the setup, it is possible to customize a 3D crystal to suit your every need by changing its shape, size, color, volume, and damage applied to its surface. The setup has been tested with Blender 3.2.1 and works best with Cycles.