Chatkalite

Chatkalite
General
Category	Sulfide mineral
Formula (repeating unit)	Cu6Fe2+Sn2S8
IMA symbol	Ctk
Strunz classification	2.CB.20
Crystal system	Tetragonal
Crystal class	Scalenohedral (42m) H-M symbol: (4 2m)
Space group	P4m2
Unit cell	a = 7.61(1) Å, c = 5.373(5) Å; Z = 1
Identification
Color	Rose to brown orange; Pale rose in reflected light
Crystal habit	Rounded grains, to 100 μm within tetrahedrite
Mohs scale hardness	4.5
Diaphaneity	Opaque
Specific gravity	5.00 (calculated)
References

Chatkalite is a copper, iron, tin sulfide mineral with formula Cu₆Fe²⁺Sn₂S₈. It crystallizes in the tetragonal crystal system and forms as rounded disseminations within tetrahedrite in quartz veins.

Physical properties

Chatkalite can have sizes ranging from rounded grains of about 100 micron when found within a tetrahedrite. It has a metallic luster, a hardness of 274 on the Vickers scale and a hardness of 4.5 on the Mohs scale. It has a color of pale rose in reflected light with no internal reflection. Its diaphaneity can be described as opaque. It does not exhibit any cleavage or twinning properties. Chatkalite is anisotropic which is characteristic of the stannite group. Its anisotropic intensity is a weak shade of brown.

Occurrences

Chatkalite was first located in the sulfide bearing quartz veins of the Chatkal-Kuramin Mountains in eastern Uzbekistan in 1981. Chatkalite has also been located in few other places since then namely Ubertad Mine, Quirulvica Province of Santiago de Chuco, Peru, Mine McCoy, McCoy district, Lander County, Nevada US and Eugenia Maria Vein, Cerro Shortcut, Catamarca, Argentina. A few other minerals are also closely associated to chatkalite based on locality, these are cassiterite, hermisite and hessite.

Unique characteristics

One of the rare characteristic of chatkalite is the fact that it has quaternary Bravais lattice metric singularity along with mawsonite. This means that there are four different lattices with three different symmetries that are all consistent with the same set of d spacings. The mineral chatkalite and mawsonite are considered highly specialized because they can produce cubic I tetragonal P, orthorhombic F, and orthorhombic P lattices.

Etymology

Chatkalite was discovered in 1981 around the Chatkal Mountains of Uzbekistan in an unknown locality. It was given the name chatkalite because of this region where it was discovered.

Further reading

• Anthony, J. W. (19902003). Handbook of mineralogy. Tucson, Ariz.: Mineral Data Pub.
• Bohmer, H. (1964). Introduction. Mineralogy of the tetrahedrite series (p. 12). Ann Arbor : UMI Dissertation publishing.
• Chatkal valley. (n.d.). . The nature that could steal your heart. Retrieved November 3, 2013, from https://web.archive.org/web/20131216042007/http://www.people-travels.com/uzbekistan-cities/tashkent/chatkal.html
• Fleischer, Michael; Burns, Roger G.; Cabri, Louis J.; Francis, Carl A.; Pabst, Adolf (1 April 1982). "New Mineral Names". American Mineralogist. 67 (3–4): 413–418.
• Márquez-Zavalía, M. F.; Galliski, M. A. (June 2007). "Chatkalita, nekrasovita y otros minerales del grupo de la estannita de Veta María Eugenia, Cerro Atajo, Catamarca" [Chatkalite, nekrasovite and other minerals from the stannite group of Veta María Eugenia, Cerro Atajo, Catamarca]. Revista de la Asociación Geológica Argentina (in Spanish). 62 (2): 289–298.
• Mighell, Alan D. (2001). "Ambiguities in powder pattern indexing: A ternary lattice metric singularity". Powder Diffraction. 16 (3): 144–148. Bibcode:2001PDiff..16..144M. doi:10.1154/1.1369789. S2CID 96727801.
• Pieczka, A.; Golebiowska, B.; Parafiniuk, J. (1 August 2009). "Conditions Of Formation Of Polymetallic Mineralization In The Eastern Envelope Of The Karkonosze Granite: The Case Of Redziny, Southwestern Poland". The Canadian Mineralogist. 47 (4): 765–786. doi:10.3749/canmin.47.4.765.