Lithosite


Lithosite		K₃ [HAl₂Si₄O₁₃]

Morphology:
	Irregular grains 1-3 mm in size.

Physical properties:
	Hardness: 5½ on Mohs scale Density = 2.51 gm/cm³(Measured) 2.54 gm/cm³(Calculated) Luster: vitreous Streak: White


Optical properties:
	Color: Colorless; bright pink after X-ray irradiation for at least 8 months. Biaxial (+) α = 1.510(2) , β = 1.513(2), γ = 1.527(2); 2V: Measured: 47° , Calculated: 52°		Colorless crystals of lithosite from Vuonnemiok River Valley, Khibiny Massif, Murmansk Oblast, Russia.

Crystallography:
	Unit cell: a 15.197, b 10.233, c 8.435 Å, β 90.21° Z = 2. Space group: n.d.

Name:
	The name is from the Greek lithos meaning stone, because it is composed of the most abundant components in the Earth's crust.

Crystal structure:
	The framework topology of the –LIT zeolite consists of three types of secondary building units of 6 or 4-[1,1] or 4-2 and includes four, six, and eight-membered rings (4, 6, 8MR) of tetrahedral atoms. It is characteristic of this topology to include a pseudo 10MR accompanied by terminal silanol groups. The –LIT type structure has a three-dimensional pore structure, and 8MR contacts pseudo 10MR. Potassium cations are densely accommodated in micropores.
	The framework of lithosite, with Si/Al framework in beige,O atoms in red and K atoms in purple.

Chemical composition:
	Electron microprobe analysis of a sample from Khibiny massif, Russia corresponds to K_5.84Al_3.94Si _8.08O₂₅ · 2.5H₂O.

Occurrences:
	Lithosite is a natural zeolite that was first discovered in Vuonnemiok River Valley, Khibiny Massif, Murmansk Oblast, Russia. Occurs in veins of ultra-agpaitic pegmatite cutting nepheline syenites (rischorrites). Standard samples are preserved in the Fersman Mineralogical Museum, USSR Academy of Sciences, and the Museum of the Geological Institute of the Kola Branch, USSR Academy of Sciences.

References:
	Khomyakov, A. P., Chernitsova, N. M., and Chistyakova, N. I. (1983) Lithosite K₆Al₄Si₈O₂₅· 2H₂O — a new mineral. International Geology Review, 25(6), 741-744. Pudovkina, Z. V., Solov'eva, L. P., and Pyatenko, Y. A. (1986). Crystal structure of lithosite K₃[HAl₂Si₄O₁₃]. In Soviet Physics Doklady (Vol. 31, p. 941). Updated: May 2025.