Zinnwaldite information

Zinnwaldite
Zinnwaldite
	Fluorapatite with topaz on zinnwaldite and quartz
General
Category	Phyllosilicate mineral
Formula; (repeating unit)	KLiFeAl(AlSi3)O10(OH,F)2
IMA symbol	Znw
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) ; (same H-M symbol)
Space group	Cc (no. 9)
Unit cell	a = 5.29, b = 9.14 ; c = 10.09 [Å]; β = 100.83°
Identification
Color	Gray-brown, yellow-brown, pale violet, dark green, color zoning common
Crystal habit	Well-formed short prismatic or tabular crystals, pseudohexagonal, in rosettes or fan-shaped groups; lamellar or scaly aggregates; disseminated.
Twinning	On composition plane {001}, twin axis [310]
Cleavage	Perfect basal {001}
Fracture	Uneven
Tenacity	Laminae °exible, elastic
Mohs scale hardness	3.5 - 4.0
Luster	Pearly to vitreous
Streak	White
Diaphaneity	Transparent to translucent
Specific gravity	2.9 - 3.1
Optical properties	Biaxial (-)
Refractive index	nα = 1.565 - 1.625 nβ = 1.605 - 1.675 nγ = 1.605 - 1.675
Birefringence	0.040 - 0.050
Pleochroism	Distinct, X = colorless to yellow-brown; Y = gray-brown; Z = colorless to gray-brown
2V angle	0 - 40°
References

Zinnwaldite, KLiFeAl(AlSi₃)O₁₀(OH,F)₂, potassium lithium iron aluminium silicate hydroxide fluoride is a silicate mineral in the mica group. The IMA status is as a series between siderophyllite (KFe₂Al(Al₂Si₂)O₁₀(F,OH)₂) and polylithionite (KLi₂AlSi₄O₁₀(F,OH)₂) and not considered a valid mineral species.^[4]

^ 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.
^ Cite error: The named reference Handbook was invoked but never defined (see the help page).
^ Webmineral data
^ ^a ^b Cite error: The named reference Mindat was invoked but never defined (see the help page).
^ Rieder, M.; Hybler, J.; Smrcok, L.; Weiss, Z. (1996). "Refinement of the crystal structure of zinnwaldite 2M_1". European Journal of Mineralogy. 8 (6): 1241–1248. doi:10.1127/ejm/8/6/1241.

[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.

[Handbook-2] Cite error: The named reference Handbook was invoked but never defined (see the help page).

[3] Webmineral data

[Mindat-4] Cite error: The named reference Mindat was invoked but never defined (see the help page).

[5] Rieder, M.; Hybler, J.; Smrcok, L.; Weiss, Z. (1996). "Refinement of the crystal structure of zinnwaldite 2M_1". European Journal of Mineralogy. 8 (6): 1241–1248. doi:10.1127/ejm/8/6/1241.

Zinnwaldite information

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Zinnwaldite

List of gemstones by species

List of minerals

Mica

Lithium

Spodumene

Rubidium

Lithium iron phosphate

Tourmaline

Lithium chloride

Lithium nickel cobalt aluminium oxides

Alkali metal

Lithium atom

Lithium hydroxide

List of mineral symbols

Lithium nitride

Lithium diisopropylamide

Lithium tantalate

Petalite

Lepidolite

Gilman reagent

Lithium citrate

Lithium hexafluorophosphate

Lithium nickel manganese cobalt oxides