Base materials with high potential

Very good materials

Best of the best

• diamond and its polymorphs including hexagonal diamond aka lonsdaleite

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• moissanite - SiC - high heat resistance
• stishovite and seifertite - metastable ultrahard and dense SiO₂ polymorphs
• simple titanium gemstones including: TiN TiP TiC TiSi₂ TiB₂ TiO₂ Ti₂O₃

Simple rutile structure & hard

• rutile TiO₂
• stishovite - metastable SiO₂ polymorph - rutile structure & very hard and dense

Neo-polymorphs with rutile structure
See: the stishovite continuum on the page about silicon
Silicon group: GeO₂, SnO₂, β-PbO₂
Other: MnO₂, FeSbO₄

Simple salt structures

• MgO periclase

Some transition metal monoxides (Typical: Max 1300-1900°C - Mohs 5-6)

• TiO hongquiite
• MnO Manganosite - (Mn is less abundant)
• FeO wüstite
• NiO brommelite - (Ni is not too abundant on earth but very abundant on metallic asteroids)

V vanadium, Cr chromium, Co cobalt do that too but
these elements are more scarce thus not included as pure high volume base materials here

Other

• spinell MgAl₂O₄ - very hard and cubic

Materials with some weakness

Con: low crystal structure symmetry

• leukosapphire - very hard
• quartz - and other low density polymorphs of SiO₂

Con: Rather soft materials

• calcite and aragonite

Others

• garnets - hard and cubic (but big unit cell)
• brommelite BeO - very hard but beryllium is scarce and poisonous