Zektzerite

Zektzerite
	Zektzerite
General
Category	Inosilicate
Formula; (repeating unit)	LiNa(Zr,Ti,Hf)Si6O15
Strunz classification	9.DN.05
Crystal system	Orthorhombic
Crystal class	Dipyramidal (mmm) ; H-M symbol: (2/m 2/m 2/m)
Space group	Cmca
Identification
Formula mass	529.66 g/mol
Color	Colorless to pink, cream, or white; commonly zoned
Crystal habit	Stout pseudohexagonal prisms
Cleavage	{100} and {010} perfect
Mohs scale hardness	6
Luster	Vitreous to pearly
Streak	White
Diaphaneity	Translucent to transparent
Specific gravity	2.79
Optical properties	Biaxial (-)
Refractive index	nα = 1.582 nβ = 1.584 nγ = 1.584
Ultraviolet fluorescence	Light yellow
References	[1][2][3]

The mineral zektzerite is a member of the tuhualite group and was first found in 1966 by Seattle mineralogist Benjamin Bartlett "Bart" Cannon. It was discovered in the Willow creek basin below Silver Star mountain in miarolitic cavities within the alkaline riebeckite granite phase of the Golden Horn batholith, Okanogan County, Washington.[2] It is named for Jack Zektzer (born 1936), mathematician and mineral collector of Seattle, Washington.[1]

The mineral was misidentified as alkali beryl (morganite) at that time. Subsequently, in September, 1975, additional specimens of the mineral were found in a float boulder on the north side of Kangaroo Ridge at an approximate elevation of 6500 feet; it was recognized that the material was not beryl.[4]

Properties

Synthesis: by fusion of Li₂CO₃, Na₂CO₃, SiO₂, ZrO₂. The resulting material has a brilliant blue white fluorescence under short wave ultraviolet light.

Occurrence

Zektzerite is a mineral of agpaitic granites with arfvedsonite. It occurs with smoky quartz, microcline, okanoganite, sogdianite, astrophyllite, and zircon. It is found in cavities as euhedral crystals in the agpaitic-granite phase of the Golden Horn batholith, Okanogan County, Washington. It also occurs in blocks of pegmatite as rock-forming grains in a moraine of the Dara Pioz glacier in northern Tajikistan; in the Del Salto pluton in Aysén Province, Chile; Virikkollen, Haneholmveien, Sandefjord, Norway; as euhedral crystals at Ampasibitika, Ampasindava Peninsula, Madagascar; and as gemmy crystals up to 3 cm from Mt. Malosa Malawi.[3]

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References

http://webmineral.com/data/Zektzerite.shtml Webmineral
http://rruff.geo.arizona.edu/doclib/hom/zektzerite.pdf Mineral Handbook
http://www.mindat.org/min-4390.html Mindat
Dunn et al.: Zektzerite: a new lithium sodium zirconium silicate related to tuhualite and the osumilite group, American Mineralogist, v. 62, p. 416-20 (1977)

Die Seltene Mineralien von Dara-i-Pioz in Hochgebirge Tadshikistans Lapis v. 16(12) p. 42-48 (1991)
Peralkaline rocks in the late Cretaceous Del Salto pluton Eastern Patagonian Andes Aisen Chile Revista Geologica de Chile v. 29 #1 July 1992 p. 3-15
Glasser, F. P., Marr J. Synthesis of anhydrous silicates containing double chain anions Si6O15 (6-): Proceedings British Ceramic Society No. 28 p. 73-89 June 1979

Guastoni, Alessandro; Pezzotta, Frederico and Zorzi, Frederico: Neufunde aus Alkali Pegmatiten am Mount Malosa Malawi Lapis 3 (2008) p. 38-41

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[Webmin-1] ttp://webmineral.com/data/Zektzerite.shtml Webmineral

[Handbook-2] ttp://rruff.geo.arizona.edu/doclib/hom/zektzerite.pdf Mineral Handbook

[Mindat-3] ttp://www.mindat.org/min-4390.html Mindat

[4] Dunn et al.: Zektzerite: a new lithium sodium zirconium silicate related to tuhualite and the osumilite group, American Mineralogist, v. 62, p. 416-20 (1977)