Unnamed (gamma-alumina)
Invalid as an unnamed mineral
This page is currently not sponsored. Click here to sponsor this page.
Formula:
γ-Al2O3
Crystal System:
Isometric
Polymorph of:
Structurally, the Al-analogue of maghemite.
A generally synthetic, gamma polymorph of alumina. It may, however, be an important constituent of some natural pyrometamorphic rocks (Ł. Kruszewski PXRD data, e.g. Ciesielczuk et al., 2015). It may also stand for a solid solution between Al2O3 and SiO2 known as "silicon spinel" (McHale et al., 1997). As such, it may be identical to 'Silicon Spinel'.
Paglia (2004) reports the following calcination pathway: gibbsite → böhmite → γ-Al2O3 → δ-Al2O3 (synthetic equivalent of deltalumite) → θ-Al2O3 (synthetic equivalent of UM1990-23-O:Al) → α-Al2O3 (corundum).
A generally synthetic, gamma polymorph of alumina. It may, however, be an important constituent of some natural pyrometamorphic rocks (Ł. Kruszewski PXRD data, e.g. Ciesielczuk et al., 2015). It may also stand for a solid solution between Al2O3 and SiO2 known as "silicon spinel" (McHale et al., 1997). As such, it may be identical to 'Silicon Spinel'.
Paglia (2004) reports the following calcination pathway: gibbsite → böhmite → γ-Al2O3 → δ-Al2O3 (synthetic equivalent of deltalumite) → θ-Al2O3 (synthetic equivalent of UM1990-23-O:Al) → α-Al2O3 (corundum).
Unique Identifiers
Mindat ID:
53553
Long-form identifier:
mindat:1:1:53553:9
IMA Classification of Unnamed (gamma-alumina)
IMA status notes:
Unnamed (probably invalid)
Chemistry of Unnamed (gamma-alumina)
Mindat Formula:
γ-Al2O3
Elements listed:
Crystallography of Unnamed (gamma-alumina)
Crystal System:
Isometric
Class (H-M):
m3m (4/m 3 2/m) - Hexoctahedral
Space Group:
Fd3m
Setting:
Fd3m
Comment:
spinel-type structure (e.g., Paglia, 2004)
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Internet Links for Unnamed (gamma-alumina)
mindat.org URL:
https://www.mindat.org/min-53553.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
Mineral Dealers:
References for Unnamed (gamma-alumina)
Reference List:
Trokhimets, A. I.; Mardilovich, P. P.; Lysenko, G. N. (1979) IR spectra of the hydroxyl layer of γ-Al2O3. Journal of Applied Spectroscopy, 30. 625-628 doi:10.1007/bf00608427
