Aqualite

Aqualite
Aqualite
General
Category	Silicate mineral, Cyclosilicate
Formula; (repeating unit)	(H3O)8(Na,K,Sr)5Ca6Zr3Si26O66)(OH)9Cl
IMA symbol	Aq[1]
Strunz classification	9.CO.10
Crystal system	Trigonal
Crystal class	Pyramidal (3) ; H-M symbol: (3)
Space group	R3
Unit cell	a = 14.08, c = 31.24 [Å] (approximated); Z = 3
Identification
Color	Pink (pale)
Crystal habit	idiomorphic crystals (max. 3 cm)
Cleavage	None
Fracture	Conchoidal
Mohs scale hardness	4–5
Luster	Vitreous
Streak	White
Diaphaneity	Translucent
Density	2.58 (measured), 2.66 (calculated)
Optical properties	Uniaxial (+)
Refractive index	nω = 1.57, nε = 1.57 (approximated)
Pleochroism	Colorless to pink (W), pink (E)
Ultraviolet fluorescence	dull yellow (weak)
References	[2][3]

Aqualite is a very rare mineral of the eudialyte group, with formula (H₃O)₈(Na,K,Sr)₅Ca₆Zr₃SiSi(Si₂₄O₆₆)(OH)₉Cl.[2][3] 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.[4] Aqualite is unique among the eudialyte group in being hydronium-rich (the only other eudialyte-group species with essential hydronium, is the recently discovered ilyukhinite).[2] Among the other representatives of the group it also distinguish in 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 high content of water in the mineral.[3][4]

Notes on Chemistry

Elements occurring as admixtures in aqualite include barium, iron, rare-earth elements (including cerium), titanium, aluminium and trace niobium.[3]

Occurrence and association

Aqualite was discovered among peralkaline pegmatites of the Inagli massif, Sakha-Yakutia, Russia. Associated minerals are aegirine, batisite, eckermanite, innelite, lorezenite, natrolite, microcline, thorite, and galena.[3]

Origin

Aqualite is thought to be formed by ion exchange transformation of a precursor mineral.[3]

References

Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
"Aqualite: Aqualite mineral information and data". Mindat.org. Retrieved 2016-03-08.
Khomyakov, A. P., Nechelyustov, G. N., and Rastsvetaeva, R. K., 2007: Aqualite, a new mineral species of the eudialyte group from the Inagli alkaline pluton, Sakha-Yakutia, Russia, and the problem of oxonium in hydrated eudialytes. Geology of Ore Deposits 49(8), 739–751.
Johnsen, O., Ferraris, G., Gault, R. A., Grice, D. G., Kampf, A. R., and Pekov, I. V., 2003. The nomenclature of eudialyte-group minerals. The Canadian Mineralogist 41, 785–794.

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.

[1] Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.

[Mindat-2] "Aqualite: Aqualite mineral information and data". Mindat.org. Retrieved 2016-03-08.

[GOD-3] Khomyakov, A. P., Nechelyustov, G. N., and Rastsvetaeva, R. K., 2007: Aqualite, a new mineral species of the eudialyte group from the Inagli alkaline pluton, Sakha-Yakutia, Russia, and the problem of oxonium in hydrated eudialytes. Geology of Ore Deposits 49(8), 739–751.

[CanMin-4] Johnsen, O., Ferraris, G., Gault, R. A., Grice, D. G., Kampf, A. R., and Pekov, I. V., 2003. The nomenclature of eudialyte-group minerals. The Canadian Mineralogist 41, 785–794.