Aqualite: Properties and Occurrences

Aqualite is a very rare mineral of the eudialyte group, with formula (H3O)8(Na, K, Sr)5Ca6Zr3SiSi(Si24O66)(OH)9 Cl. The formula given does not show the presence of cyclic silicate groups. The original formula was extended to show the presence of silicon at both M3 and M4 sites, according to the nomenclature of the eudialyte group.

General Information:

  • Category: Silicate mineral, Cyclosilicate
  • Formula: (H3O)8(Na,K,Sr)5Ca6Zr3SiSi(Si24O66)(OH)9 Cl
  • Crystal system: Trigonal.

Properties

Aqualite is unique among the eudialyte group in being hydronium-rich. Among the other representatives of the group it also distinguishes in the splitting of the M1 site into two sub-sites, both occupied by calcium. Thus, its symmetry is lowered from typical for most eudialytes R3m (or R-3m) to R3. The name refers to the high content of water in the mineral.

  • Color: Pink (pale)
  • Crystal habit: idiomorphic crystals (max. 3 cm)
  • Fracture: Conchoidal
  • Mohs scale hardness: 4–5
  • Luster: Vitreous
  • Streak: White
  • Diaphaneity: Translucent
  • Density: 2.58 (measured), 2.66 (calculated)
  • Optical properties: Uniaxial (+)

Occurrence and association

Aqualite was discovered among peralkaline pegmatites of the Inagli massif, Sakha-Yakutia, Russia. Associated minerals are aegirine, batisite, eckermannite, innelite, lorenzenite, natrolite, microcline, thorite, and Galena.

 

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