White sapphire

Advantages:

• very hard material (Mohs 9 – defining mineral), very high heat conductivity
• made out of the extremely common element aluminum (more common than carbon)
• thermodynamically stable not just metastable thus very heat resistant

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• Crystal structure: trigonal

It is of slightly less high symmetry than other interesting base materials.
Maybe look at metastable polymorphs at the eventual cost of somewhat less heat resistance?

Terminology

Note: The page uses the term "leukosapphire" instead of just "sapphire" because
just sapphire is often associated with a blue to black variant where the color is caused by metal impurities.
A base material for gemstone metamaterial technology would be perfectly impurity free and colorless clear though.
Like a leukosapphire. Just even more clear.

Related

• Tistarite Ti₂O₃ has the same structure. => neo-polymorph series?
• Gemstone like compounds with high potential – Gemstone like compounds
• Corundum structure – Simple crystal structures of especial interest
• Aluminum oxides
• Moissanite is also an extremely heat resistant base material.
• Diamond is much less heat and oxidation resistant.
• Both diamond and moissanite have higher crystal structure symmetry than leukosapphire

Polymorphs

Deltalumite Al₂O₃ (δ form of corundum, polymorph of sapphire) – tetragonal – Mohs ? –

• (on mineralienatlas.de)
• (on mindat.org)
• (on wikidata)

Paper: "Deltalumite, a new natural modification of alumina with spinel-type structure"

• Researchgate Jannuary 2019 [1]
• Researchgate December 2020 [2]
• (semanticscholar) << Images!

How to spell this ??

• Delt-alumite?
• Delta-lumite?
• Delta-alumite?

External links

• Wikipedia Sapphire
• materialsproject.org [3]
• mineralienatlas (de) [4]
• Strukturtypendatenbank uni-freiburg: [5]
• Wikidata leukosapphire: https://www.wikidata.org/wiki/Q3831236