fraipontite

{{Short description|Zinc aluminium silicate mineral}}

{{Infobox mineral

| name = Fraipontite

| image = Fraipontite-sea52a.jpg

| imagesize = 260px

| alt =

| caption = Pockets of minute pearly white fraipontite crystals with green smithsonite from Laurium, Greece (size: 1.4 x 1.0 x 0.9 cm)

| category = Phyllosilicate

| formula = {{chem2|(Zn,Al)3(Si,Al)2O5(OH)4}}

| IMAsymbol = Fpt{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}

| molweight =

| strunz = 9.ED.15

| system = Monoclinic

| class = Domatic (m)
(same H-M symbol)

| symmetry = Cm

| unit cell = a = 5.34, b = 9.21
c = 14.12 [Å]; β = 93.2°; Z = 2

| color = Blueish, yellow white light green

| colour =

| habit = Fibrous to porcelaneous massive

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| mohs = 3.5 – 4

| luster = Silky

| streak = White to pale green

| diaphaneity = Opaque to translucent

| gravity = 3.08 – 3.10

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| opticalprop = Biaxial (-)

| refractive = n_α = 1.620 n_β = 1.624 n_γ = 1.624

| birefringence = δ = 0.004

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| 2V = Measured: 15° to 20°

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}}

Fraipontite is a zinc aluminium silicate mineral with a formula of {{chem2|(Zn,Al)3(Si,Al)2O5(OH)4}}.[http://rruff.geo.arizona.edu/doclib/hom/fraipontite.pdf Handbook of Mineralogy][http://www.mindat.org/min-1588.html Mindat.org]

It is a member of the kaolinite-serpentine mineral group and occurs as an oxidation product of zinc deposits. It occurs with smithsonite, gebhardite, willemite, cerussite and sauconite.

It was first described in 1927 for an occurrence in Vieille Montagne, Verviers, Liège Province, Belgium. It was named for Julien Jean Joseph Fraipont (1857–1910), and Charles de Fraipont, geologists of Liege, Belgium.[http://webmineral.com/data/Fraipontite.shtml Webmineral data for fraipontite] In addition to the type locality in Belgium, it has been reported from Tsumeb, Namibia; Laurium, Greece; Swaledale, North Yorkshire, England; the Silver Bill mine, Cochise County, Arizona, the Blanchard Mine, Socorro County, New Mexico and the Mohawk mine, San Bernardino County, California in the US; and from the Ojuela mine, Mapimi, Durango, Mexico.

A synonym of the fraipontite is the zinalsite, which was reported in 1956 for an occurrence in Kazakhstan.[http://webmineral.com/data/Zinalsite.shtml Zinalsite on Webmineral][http://www.mindat.org/min-4404.html Zinalsite on Mindat]