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Formula: Ti10Fe3O3
Alloy with oxygen, titanium-bearing mineral
Crystal system: Hexagonal
Specific gravity: 5.355 calculated for the empirical formula
Environments
Maurogemmiite is a new mineral, approved in 2023 and to date (January 2026) reported only from the type
locality.
Localities
At the type locality, Orebody 31, Luobusha Mine, Luobusha ophiolite, Qusum County, Shannan Prefecture, Tibet, China,
maurogemmiite and paulrobinsonite are two new (in 2023) mineral
species in a fragment 0.45mm × 0.8mm in size extracted from the
chromitite orebody. The fragment comprises
(1) an alloy core composed entirely of a ‘patchwork quilt’ of titanium-rich
alloys, including
hexagonal titanium (α-titanium) and several phases composed of Ti, Si, Fe and
Ni in varying proportions, including maurogemmiite and
paulrobinsonite. Another major constituent of the alloy core is an
intergrowth of wangxibinite and a
titanium nitride.
Maurogemmiite forms irregular grains up to 30 μm across enclosed in
paulrobinsonite, which isolated it from the
wangxibinite + osbornite
intergrowth.
(2) a nearly complete inner rim of hexagonal titanium (α-titanium) about 20 to
70 µm thick with a border about 10 µm thick of a Ti–Si alloy.
(3) an incomplete outer rim of coesite,
kyanite and an amorphous phase containing SiO2,
Al2O3, TiO2, and a little K2O, Na2O and MgO. These phases are
associated with subordinate amounts of native Fe, TiO2-II (a high-pressure polymorph of
rutile with the αPbO2 structure),
osbornite, qingsongite and
unidentified Ti–Si and Ti–Si–Al oxides. In addition, a Ti–Si alloy also associated with
coesite and osbornite in the outermost
rim of the fragment is P-free wenjiite.
Kyanite occurs as discrete cross-cutting prisms up to 50 μm long and 4 μm wide,
whereas coesite forms elongate multigranular aggregates interpreted to be
pseudomorphic after stishovite
prisms. Conditions consistent with the occurrence of stishovite and
TiO2-II are about 12 GPa pressure and about 1300°C temperature, whereas the inversion of
stishovite to coesite suggests a
decrease of pressure to 7 to 8 GPa
(MM 89.855–871).
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