Tinaksite

Tinaksite
General
Category	Silicate mineral
Formula (repeating unit)	K2Na(Ca,Mn^2+)2Ti[O|Si7O18(OH)]
Strunz classification	9.DG.75
Crystal system	Triclinic
Identification
Color	Pink, Pale yellow, Light brown
Crystal habit	Fibrous, crystalline or Prismatic, crystalline, or Radial, crystalline
Crystal symmetry	Triclinic - pinacoidal H-M symbol 1 Space group P1
Cleavage	Perfect in one direction, indistinct in one direction
Mohs scale hardness	6
Luster	Vitreous to glassy
Streak	White
Diaphaneity	Transparent to Translucent
Specific gravity	2.82
Density	2.82
Optical properties	Biaxial (+)
Refractive index	nα = 1.593 nβ = 1.621 nγ = 1.666
Birefringence	δ = 0.073
References	[1][2][3]

Tinaksite (K₂Na(Ca,Mn²⁺)₂Ti[O|Si₇O₁₈(OH)])^[2] is a mineral found in northern Russia. Tinaksite can be grayish-white, yellowish, orange, or brown,^[1] and it is often found in charoite.^[4] Its name is derived from its composition: titanium (Ti), sodium (Na) potassium (K) and silicon (Si). International Mineralogical Association first recognized tinaksite as a mineral in 1965.

References

1. http://webmineral.com/data/Tinaksite.shtml
2. http://www.mindat.org/min-3966.html
3. Mineralienatlas
4. http://www.galleries.com/minerals/silicate/tinaksit/tinaksit.htm

External links

• Rozhdestvenskaya, I. V.; Nikishova, L. V.; Lazebnik, Y. D.; Lazebnik, K. A. (1989). "Thecrystal structure of tokkoite andits relation to the structure of tinaksite" (PDF). Zeitschrift für Kristallographie: 195–204.