Deltalumite
Deltalumite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (Al₀.₆₇ ₀.₃₃)Al₂O₄.
It crystallizes in the tetragonal crystal system (space group P-4m2). It is a member of the Spinel structural group.
Key properties: specific gravity 3.663; Vitreous luster; optically uniaxial.
IMA symbol Dal, IMA status: approved, named in 2016.
Found in pores of basaltic rock and scoria altered by volcanic fumarolic gas.
The name comes from the name of the synthetic compound δ-Al2O3.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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