Stishovite
From apm
Just like like common quartz stishovite is a polymorph of silicon dioxide (SiO2).
It may be of peculiar interest because of:
- its high hardness (mohs 8.5 to 9.5) compared to quartz (mohs 7 - defining mineral)
- it consisting of the two globally (and often locally) most common elements in earth crust
- it still featuring a reasonably simple (tetragonal) crystal structure with the rutile structure
Given both stishovite and rutile feature the same crystal structure it may be possible to mechanosynthesize checkerboard neo-polymorphic transitions by replacing some Si with with Ti in a regular pattern.