textures:
https://github.com/malcolmriley/unused-textures/blob/master/items/material_crystal_sulfur.png
https://github.com/malcolmriley/unused-textures/blob/master/items/material_crystal_blue.png
(both are licensed under Creative Commons Attribution 4.0 International https://github.com/malcolmriley/unused-textures/blob/master/LICENSE )
(which are made by malcolmriley on github)
