Formula: Pb(UO2)(Te4+O3)2
Tellurite, uranyl mineral
Crystal System: Monoclinic
Specific gravity: 5.73 measured, 7.256 calculated
Hardness: 3
Colour: Bright orange to dark orange
Solubility: Readily soluble in dilute hydrochloric acid and in dilute sodium hydroxide
RADIOACTIVE
Environments
Moctezumite is a secondary mineral in
tellurium-bearing ores (Webmin).
Pseudomorphs of
schmitterite after moctezumite have been found
(Dana).
Localities
The type locality is the Moctezuma Mine, Moctezuma, Moctezuma Municipality, Sonora, Mexico. The mine is an epithermal
(shallow depth, low temperature) quartz vein containing
gold with high contents of tellurium.
Although the mine workings went below the water table, oxidised vein material was still found mixed with unoxidised
primary minerals. The unoxidized ore was composed of
quartz, baryte,
fluorite, pyrite and native
tellurium. The oxidised ore contained, in very minor amounts,
gold, tellurite,
paratellurite, emmonsite,
chalcomenite, a copper
selenide, hydrated iron oxides,
manganese oxides, native selenium,
tetradymite, altaite,
cinnabar and wulfenite.
Moctezumite is a rare secondary mineral occurring as
minute blades and rosettes in fractures and vugs in the oxidised zone of the
quartz vein with baryte containing
gold and tellurium minerals associated
with the quartz. The largest crystal of moctezumite at the time of
discovery was 3 mm × 1 mm × 0.2 mm. Associated minerals were baryte,
pyrite, emmonsite,
limonite and other unnamed tellurites.
(AM 50.1158-1163, R&M 93.5.466-471).
Other associated minerals include schmitterite,
zemannite, burckhardtite
and tellurite
(HOM, Dana).
Moctezumite from the Moctezuma mine -
Image
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