Difference between revisions of "White sapphire"
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* There are many other possible colors from impurities/dopants. | * There are many other possible colors from impurities/dopants. | ||
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| − | * (Green) emerald is NOT a form of sapphire but a form of [[Beryl]] <br>a beryllium aluminum silicate harder than typical silicates. | + | * (Green) emerald is NOT a form of sapphire but a form of [[Beryl]] <br>a beryllium aluminum silicate harder than typical silicates. <br> [[Beryllium]] is a quite rare element so forms of beryl are not that viable as a structural material. |
== External links == | == External links == | ||
Revision as of 10:46, 16 February 2024
Terminology
"White sapphire" (meaning clear transparent colorless) because we want to focus on perfect crystals without any color giving impurities.
A base material for gemstone metamaterial technology would be perfectly impurity free and colorless clear.
Just "sapphire" usually refers to sapphires with impurities (iron and titanium ions replace aluminum ions) causing a blue to black color.
Also called lecosapphire or leukosapphire (may be more prevalent in German).
Advantages of this gem
- very hard material (Mohs 9 – defining mineral), very high heat conductivity
- made out of the extremely common element aluminum (more common than carbon in diamond or moissanite)
Possibly helpful on the Moon with carbon being scarce. - like moissanite sapphire is thermodynamically stable not just metastable like diamond thus very heat resistant
- Crystal structure: trigonal – Not as high symmetry as cubic but still good.
Maybe look at metastable Al2O3 polymorphs at the eventual cost of somewhat less heat resistance?
Related
- Deltalumite – a tetragonal polymorph of Al2O3 with spinel structure
- 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 ? –
Triavia
- (Red) ruby is just red sapphire. Color from Chromium Cr.
- Classic blue is from elements (Fe,Ti)
- There are many other possible colors from impurities/dopants.
- (Green) emerald is NOT a form of sapphire but a form of Beryl
a beryllium aluminum silicate harder than typical silicates.
Beryllium is a quite rare element so forms of beryl are not that viable as a structural material.
External links
Wikipedia
- materialsproject.org [1]
- mineralienatlas (de) [2]
- Strukturtypendatenbank uni-freiburg: [3]
- Wikidata leukosapphire: https://www.wikidata.org/wiki/Q3831236
