Agardite-(Nd) Field of view: 2 mm Locality: Level 4, Hilarion Mine, Kamariza, Lavrion District, Attica, Greece — Photo: Henk Smeets – tomeikminerals.com · CC BY 4.0
Agardite-(Nd)
Agardite is a mineral group consisting of agardite-(Y), agardite-(Ce), agardite-(Nd), and agardite-(La). They comprise a group of minerals that are hydrous hydrated arsenates of rare-earth elements (REE) and copper, with the general chemical formula (REE,Ca)Cu6(AsO4)3(OH)6·3H2O. Yttrium, cerium, neodymium, lanthanum, as well as trace to minor amounts of other REEs, are present in their structure. Agardite-(Y) is probably the most often found representative. They form needle-like yellow-green (variably hued) crystals in the hexagonal crystal system.
Intro adapted from Wikipedia (CC BY-SA).
Agardite-(Nd) is an IMA-recognized mineral species in the arsenate class, with the chemical formula NdCu²⁺₆(AsO₄)₃(OH)₆·3H₂O.
It crystallizes in the hexagonal crystal system (space group P6_3/m). It is a member of the Mixite structural group.
Key properties: Mohs hardness 3; specific gravity 3.81; White streak; Vitreous; silky (aggregates) luster; optically uniaxial.
IMA symbol Agr-Nd, IMA status: approved, named in 2010.
Found in the oxidation zone of polymetallic sulfide deposits.
It is found associated with Zálesíite, zincolivenite, azurite, malachite, calcite, goethite.
By analogy to agardite-(Y), with its rare-earth content dominated by neodymium.