Ancylite

Ancylite

Nenadkevichite with ancylite crystals on the side
General
Category Carbonate mineral
Formula
(repeating unit)
Sr(Ce,La)(CO3)2(OH)·H2O
Strunz classification 5.DC.05
Dana classification 16b.1.1.1
Crystal system Orthorhombic
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space group Pmcn
Identification
Color Light yellow, orange-yellow, yellow-brown, grey
Cleavage None
Fracture Splintery
Tenacity Brittle
Mohs scale hardness 4 - 4½
Luster Dull
Streak White
Diaphaneity Translucent
Density 3.95 g/cm3

Ancylite is a group of hydrous strontium carbonate minerals containing cerium, lanthanum and minor amounts of other rare earth elements. The composition is Sr(Ce,La)(CO3)2(OH)·H2O with ancylite-Ce enriched in cerium and ancylite-La in lanthanum.[1][2]

Ancylite was first described in 1899 for an occurrence in the Narsarsuk pegmatite in west Greenland and named from the Greek αυκιλος for curved in reference to its rounded or distorted crystal form.[1][3]

References

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