rare earth mineral

Calcioancylite-(Ce): (Ce,Ca,Sr)CO3(OH,H2O)
Calcioancylite-(Nd): Nd2.8Ca1.2(CO3)4(OH)3.H2O
Hydrated carbonates containing hydroxyl, ancylite group
Specific gravity: Calcioancylite-(Ce) 4.30. Calcioancylite-(Nd) 4.02 (Nd)
Hardness: 4 to 4½
Streak: Calcioancylite-(Nd) White
Colour: Calcioancylite-(Ce) Pink in daylight, blue-grey in fluorescent light (Dana). Calcioancylite-(Nd) pink
Solubility: Readily soluble in acids

Plutonic igneous environments
Hydrothermal environments

Calcioancylite is a rare secondary rare-earth mineral. Calcioancylite-(Ce) occurs with carbonates and alkali igneous rocks such as syenitic pegmatites (Dana).

At Mont Saint-Hilaire, Quebec, Canada, calcioancylite-(Ce) occurs in alkaline igneous rocks (HOM). At its type locality, the Seula mine, Baveno, Piedmont, Italy, calcioancylite-(Nd) was found on orthoclase in late-stage miaroles in granite, associated with orthoclase, quartz and albite (HOM, Webmin, AM76.1729).

In New york city, New York, USA, calcioancylite-(Ce) was discovered with ancylite-(Ce) as crystals on stilbite in rock that was dumped from the excavation of the 63rd Street subway tunnel (R&M 84-3.225).

At its type locality Foote mine, Cleveland county, North Carolina, USA, calcioancylite-(Ce) occurs in lithium pegmatites associated with monazite (Dana). At Cornog, Chester county, Pensylvania, USA, calcioancylite-(Ce) has been found in calcite-lined cavities in an amphibole gneiss-migmatite (similar to alpine cleft minerals of hydrothermal origin), associated with K-feldspar, natrolite, aegirine, catapleiite, perovskite, astrophyllite, titanite, apatite, anatase, synchysite, quartz, calcite, actinolite and pyrite (Dana, HOM).