- Zinnwaldite
Infobox mineral
name = Zinnwaldite
category = Phyllosilicate mineral
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formula = KLiFeAl(AlSi3)O10(OH,F)2
molweight =
color = Light brown to yellowish- or greenish-white
habit = Micaceous, platey scaly masses, pseudo-hexagonal phenocryst tablets
system =Monoclinic
twinning = On composition plane {001}, twin axis [310] .
cleavage = Perfect basal {001}
fracture = Uneven
mohs = 3.5 - 4.0
luster = Pearly to vitreous
refractive = nα = 1.565 - 1.625 nβ = 1.605 - 1.675 nγ = 1.605 - 1.675
opticalprop = Biaxial (-) 2V = 30°
birefringence = 0.040 - 0.050
pleochroism = distinct
streak = White
gravity = 2.9 - 3.1
density =
melt =
fusibility =
diagnostic =
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tenacity = Laminae flexible, elastic.
diaphaneity = Transparent to translucent
other =Zinnwaldite, KLiFeAl(AlSi3)O10(OH,F)2, is a potassium lithium iron aluminium silicate hydroxide fluoride
silicate mineral in themica group.It occurs in
greisen s,pegmatite , andquartz veins often associated withtin ore deposits. It is commonly associated withtopaz ,cassiterite ,wolframite ,lepidolite ,spodumene ,beryl ,tourmaline , andfluorite .It was first described in 1845 in
Zinnwald /Cinovec on the German-Czech Republic border.References
* [http://rruff.geo.arizona.edu/doclib/hom/zinnwaldite.pdf Handbook of Mineralogy]
* [http://webmineral.com/data/Zinnwaldite.shtml Webmineral data]
* [http://mindat.org/min-4419.html Mindat]
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