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Formula: Fe3+2Fe2+4(PO4)(OH)11.H2O
Hydrated phosphate
Crystal System: Monoclinic
Specific gravity: measured 3.11, calculated 3.08
Hardness: 4 to 4½
Streak: Olive-green, changing colour to brownish red in 10 to 12 hours
Colour: Dark green, almost black, red-brown, brownish
Luminescence: No fluorescence under UV
Solubility: Soluble in hydrochloric acid after several hours at room temperature
Environments
Carbonatites
Hydrothermal environments
Gladiusite was approved in 1998 and to date (December 2022) has been recorded only from the type locality.
Localities
At the type locality, the Kovdor Massif, Murmansk Oblast, Russia, the massif was emplaced into a metamorphic sequence
comprised mostly of amphibole-biotite
gneiss. An ultramafic core
(olivinite, pyroxenite
and diopside–olivine rocks) is
surrounded by turjaite,
melilitolite,
phlogopite-bearing
diopside–olivine rock,
garnet–amphibole–monticellite
rock, nepheline pyroxenite,
phoskorite–carbonatite
and carbonate–fluorapatite-cemented
breccias, with outer zones of alkaline rocks
(jacupirangite,
ijolite–melanocratic nephelinolite).
A well-defined fenite zone surrounds the massif.
The phoskorite–carbonatite
complex was emplaced into pyroxenites and
ijolites, and is bordered by a a fine-grained
apatite–forsterite metasomatic
rock. Postmagmatic re-activation of the fault has caused extensive rock deformation, accompanied by an influx of
hydrothermal fluids from the cooling phoskorite and
carbonatite. As a result, the hydrothermal assemblages
superimposed on the dolomite
carbonatite contain a variety of rare minerals.
Gladiusite is confined to hydrothermal assemblages from vugs in deformed and mineralised
dolomite
carbonatite. The order of crystallisation is as follows:
primary pyrrhotite
and fluorapatite → dolomite →
pyrochlore → magnetite (type I)
or pyrite → rutile →
ternovite-like phase →
catapleiite → rimkorolgite
→ bobierrite → collinsite →
juonniite →
strontiowhitlockite →
pyrrhotite (type II) → gladiusite →
strontium-bearing
collinsite → magnetite-(type
II) → chlorite → dolomite (the
minerals associated with gladiusite are in italics). Gladiusite is not associated with other hydrous
iron phosphates in these hydrothermal assemblages.
Vivianite and strengite occur in
the upper horizons of the
phoskorite–carbonatite
complex.
Gladiusite occurs as acicular masses and as freestanding radiating clusters of arrow-head crystals; clusters do
not exceed 2 mm in diameter. Acicular crystals vary from 0.5 to 7 microns thick and from 10 to 500 microns long
(CM 38.1477-1485).
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