Juonniite Mineral Data

General Information

Chemical Formula: CaMgSc(PO4)2(OH)4(H2O)
Composition: Molecular Weight = 388.35 gm)
  Oxygen 53.56 % O
  Hydrogen 2.34 % H
  Phosphorus 15.95 % P
  Scandium 11.58 % Sc
  Magnesium 6.26 % Mg
  Calcium 10.32 % Ca
Environment: Metasomatically reworked calcite-phlogopite-clinohumite-magnetite ores in a calcite-dolomite carbonatitic stockwork zone. The scandium dominant analog of overite and segelerite.
IMA Status: Approved IMA (Dana # Added)
Locality: Kovdor ultramafic alkaline complex, Yona or Juonni River (from the Russian or Finnish), Kola Peninsula, Russia).
Name Origin: The name alludes to the locality. Pronounced YO'NAITE.
Synonym: IMA96.060


Dana Class: (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen (42.11)where (AB)4 (XO4)3 Zq x(H2O) (42.11.1)Dana Group


Axial Ratios: a:b:c =0.7931:1:0.4005
Cell Dimensions: a = 15.03, b = 18.95, c = 7.59, Z = 8; V = 2,161.77 Den(Calc)= 2.39
Crystal System: Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pbca
X Ray Diffraction: By Intensity(I/Io): 9.49(1) 2.912(0.44) 2.89(0.35)

Physical Properties

Cleavage: None
Color: colorless, light yellow, yellowish brown, gray, or bright orange.
Density: 2.43
Diaphaniety: Translucent
Habits: Spherical - Spherical, rounded aggregates., Platy - Sheet forms (e.g. micas).,
Hardness: 4-4.5 - Between Fluorite and Apatite
Luminescence: Non-fluorescent.
Luster: Vitreous (Glassy)
Streak: white

Optical Properties

Optical Data: Biaxial (-), a=1.574, b=1.579, g=1.582, bire=0.0080
Pleochroism (x): none.
Pleochroism (y): none.
Pleochroism (z): none.

Other Information

References: NAME( AmMin) PHYS. PROP.(Min.Mag.,Vol.61,p736,1997) OPTIC PROP.(AmMin)
See Also: Frederic Biret

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