White sapphire
White sapphire (meaning clear transparent colorless) because we want to focus on perfect crystals without any color giving impurities.
Just "sapphire" usually refers to sapphires with impurities (iron and titanium ions replace aluminum ions) causing a blue color.
Also called lecosapphire or leukosapphire (may be more prevalent in German).
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
- 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 ? –
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
- materialsproject.org [3]
- mineralienatlas (de) [4]
- Strukturtypendatenbank uni-freiburg: [5]
- Wikidata leukosapphire: https://www.wikidata.org/wiki/Q3831236
