Agardite-(La)

Agardite is a mineral group consisting of agardite-(Ce), agardite-(Nd), agardite-(La), and agardite-(Y). They comprise a group of hydrous calcium, copper arsenate minerals which contain variable amounts of the rare elements cerium, neodymium, lanthanum and yttrium as well as trace to minor amounts of other rare earth elements. The general formula is (Ce,La,Nd,Y,Ca)Cu6(AsO4)3(OH)6·3(H2O). They form needle-like yellow green crystals in the hexagonal crystal system. The Mohs hardness is 3 to 4 and the specific gravity is 3.72.
See more at Wikipedia.org...

General Information:
 Chemical Formula:
(La,Ca)Cu6(AsO4)3(OH)6·3(H2O)
 Composition:
(Molecular Weight = 1,068.32 gm)
Calcium 0.94 % Ca
Lanthanum 9.75 % La
Copper 35.69 % Cu
Arsenic 21.04 % As
Hydrogen 1.13 % H 
Oxygen 31.45 % O 
 Empirical Formula:
La0.75Ca0.25Cu6(AsO4)3(OH)6·3(H2O)
 IMA Status:
Approved IMA (Dana # Added)
 Locality:
TL: USA, NM, Lincoln Co, Red Cloud mn
 Name Origin:
Named for the composition and for Jules Agard, Geologist, Bureau de Recherches Geologiques et Minieres, Orleans, France.
Physical Properties:
 Color:
colorless, yellowish green, or blue.
 Density:
3.72
 Diaphaniety:
Transparent
 Habits:
Acicular - Occurs as needle-like crystals., ,
 Hardness:
3-4 - Calcite-Fluorite
 Luster:
Vitreous (Glassy)
 Streak:
greenish white
More details...