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Formula: Na3(SO4)(NO3).H2O
Compound nitrate
Crystal System: Monoclinic
Specific gravity: 2.201 measured, 2.202 calculated
Hardness: 2½
Streak: White
Colour: Colourless
Solubility: Readily soluble in water
Environments
Darapskite occurs in nitrate deposits rich in sulphates. Common associates include
anhydrite, blödite,
halite and nitratine
(Mindat).
Localities
At the Roberts Massif, Queen Maud Land, Eastern Antarctica, Antarctica, and supposedly darapskite has been
reported in saline arid soil
(AM 55.1500-1517).
At the type locality, Pampa del Toro, Oficina Lautaro, Taltal, Antofagasta Province, Antofagasta, Chile,
darapskite occurs in the nitrate ore as discrete crystals in cavities, as platy masses in veins, and as granular
material admixed with other saline minerals in veins, pods, and cementing material. Delicate tabular crystals are by
far the most abundant and widespread; prismatic crystals were found at only a few localities. Veins of
darapskite, found at a few localities only, consist of imperfect tabular crystals as much as 10 cm long and 1 cm
thick. Granular darapskite is found associated with halite and
nitratine in veins, in encrustations in cavities, and in small pods or blebs
as well as in finely disseminated saline cement.
It appears that darapskite formed between 7 and 74oC.
(AM 55.1500-1517).
Associated minerals include niter,
blödite, mirabilite,
epsomite and anhydrite, as well as
halite and nitratine
(HOM).
At the Chuquicamata Mine, Chuquicamata District, Calama, El Loa Province, Antofagasta, Chile, darapskite occurs
in veins, as much as 6 inches wide, associated with kröhnkite,
blödite, mirabilite and
epsomite
(AM 55.1500-1517).
At the Funeral Mts, Amargosa Range, Inyo county, California, USA, darapskite occurs in saline material from
caves in limestone
(AM 55.1500-1517).
At the Death Valley National Park, USA, darapskite occurs in the nitrate deposits of California, where it is
associated with nitratine and niter
(AM 55.1500-1517).
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