Tistarite

A form titanium oxide with stoichometry Ti₂O₃ that is isostructural to leukosapphire Al₂O₃.
Maybe via checkerboard patterning during piezomechanosynthesis a transition is possible giving some Neo-polymorph series.

Same elements as rutile/anatase/brookite TiO₂ but different stoichometry.

• Pro: Titanium is common in earths crust (and in space)
• Pro: Hardness is high
• Pro: Crystal structure is simple
• Con? unit cell is a bit big

Overall a good base material for gemstone metamaterial technology for large scale construction.

• Formula: Ti₂O₃
• Hardness Mohs 8.5 (quite a bit harder than rutile which has: Mohs 6.0 to 6.5)

• Crystal system: Trigonal (the same as sapphire but different unit cell)
• Density ~4.53g/ccm
• Refractive index: ?? – likely quite high

Misc trivia:
Titanium is in a unusual trivalent form here
(as in grossmanite a titanium chain silicate).

Isostructural gems (Hematite structure)

• White sapphire Al₂O₃
• Hematite Fe₂O₃

See: Simple crystal structures of especial interest

Related

• Titanium

Other polymorphs of same formula:

• Rutile
• Anatase
• Brookite

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Isostructural gems:

• Leukosapphire (gem grade corundum) Fe₂O₃ – Mohs 9 (defining mineral) – optically transparent
• Hematite Fe₂O₃ – Mohs 5-6 (rather soft in comparison) – optically metallic
• Escolaite Cr₂O₃ – Mohs 8.0-8.5 – Cr is not too abundant – optically metallic black?
• Karelianite V₂O₃ – Mohs 8-9 – V is not too abundant – optically metallic

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• Deltalumite … an aluminum oxide with oxospinel structure instead of the typical sapphire/corundum/hematite structure (unusual).

External links

• Wikipedia: Tistarite (quite limited info there as of 2021-06)
• mineralientalas.de: Tistarite (3D structure)
• www.mindat.org: Tistarite (3D structure)