Bromellite
BeO, beryllium monoxide, Mohs 9, hexagonal
Beryllium is rare so usefulness as structural material is limited.
Related
- Beryl (clear form of emerald) … a hard beryllium aluminum silicate
- Beryllium
- Base materials with high potential – not one due to elemental scarcity
- Diamondoid
- Limits of construction kit analogy