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Formula: Ce4MgFe3+2Ti2O8(Si2O7)2
Sorosilicate (Si2O7 groups), chevkinite group,
paramorph of chevkinite-(Ce),
cerium- and
titanium- bearing mineral
Crystal System: Monoclinic
Specific gravity: 4.29 to 4.45
Hardness: 5½
Streak: Brown
Colour: Brown, reddish brown, black
Solubility: Gelatinises in hydrochloric acid and dissolves in hot sulphuric acid
Weakly RADIOACTIVE
Environments
Plutonic igneous environments
Pegmatites
Sedimentary environments
Hydrothermal environments
Lunar environments
Perrierite-(Ce) occurs as a minor accessory mineral in volcanic ash beds, but it is more commonly found in alkalic
or peralkaline granites,
granite pegmatites,
syenites and syenitic
pegmatites; it also occurs in
tuffaceous sands, and rarely in
granodiorites or
anorthosite and gabbro
(Dana).
The paramorphs chevkinite-(Ce) and
perrierite-(Ce) are the most common members of the chevkinite group. Both
have been reported from a wide range of igneous, metamorphic, and hydrothermal rocks types, but occurrences in
mafic rocks are rare.
Chevkinite-(Ce) and/or perrierite-(Ce) occur with other
titanium-, zirconium- and
rare-earth-element- bearing accessory phases in tholeiitic
dolerite from Western Australia, and in moon rocks, and they are more
abundant than has been recognised previously in mafic igneous rocks.
Chevkinite-(Ce) and perrierite-(Ce) from
mafic rocks have distinctive chemical compositions with higher
zirconium content than that recorded in examples from most other common rock
types. Among mafic rocks, two groups are recognised: the high-Fe group
(>8 wt% FeO) is chevkinite-(Ce), while the low-Fe group (<8 wt% FeO) is
consistent with perrierite-(Ce), and both minerals can occur within a single hand specimen
(AM 99.1911-1921.).
Localities
The type locality is the Nettuno seashore, Nettuno, Metropolitan City of Rome Capital, Lazio, Italy.
Tranquillity Base, Mare Tranquillitatis, The Moon. Chevkinite-(Ce) and/or
perrierite-(Ce) occur with other titanium-,
zirconium- and rare-earth-element- bearing accessory phases in rocks brought back
from the Apollo 11 landing site
(AM 99.1911-1921.).
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