Images
Formula: Ca2Na3(SO4)3OH
Anhydrous sulphate, hedyphane group,
apatite supergroup
Crystal System: Hexagonal
Specific gravity: 2.786 measured, 2.83 calculated
Hardness: 2 to 3
Streak: White
Colour: Colourless, white
Solubility: Low solubility in water (etch-pits develop after prolonged contact with distilled water). Grains
develop rounded edges in hydrochloric and sulphuric acid (both cold and hot). Hot nitric acid produces corroded
edges, and a superficial film of white powdery material. Cesanite crystals are entirely dissolved in
aqua regia after a short time
(Mindat).
Environments
Volcanic igneous environments
Hydrothermal environments
Localities
At the type locality, the Cesano 1 well, Cesano geothermal field, Metropolitan City of Rome Capital, Lazio, Italy,
cesanite occurs both as a solid, 1 cm thick, vein and as a cavity filling of an explosive
breccia in core samples from the well, in volcanic and pyroclastic
rocks. Other sulphates identified in the core samples include gypsum,
anhydrite, aphthitalite,
görgeyite, kalistrontite
and glauberite
(AM 67.621-624, Mindat).
The Măgurici Cave, Răstoci, Sălaj County, Romania, hosts a diverse assemblage of minerals. The phosphatisation of
illite and
montmorillonite
clay-rich sediments, located on the cave's floor, lead to the formation
of taranakite and
francoanellite. Mineral assemblages precipitated at the boundary
between limestone bedrock and guano deposits are dominantly
hydroxylapatite, brushite,
ardealite and monetite. A
number of sulphate minerals, including gypsum,
bassanite, mirabilite and
cesanite, were precipitated along with the phosphates
(EJM 15.4.741–745).
Back to Minerals