gananite

{{short description|Rare bismuth fluoride mineral}}

{{Infobox mineral

| name = Gananite

| category = Halide mineral

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| image =

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| formula = BiF₃

| IMAsymbol = Gan{{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 = 3.AC.20

| system = Cubic

| class = Hextetrahedral ({{overline|4}}3m)
H-M symbol: ({{overline|4}} 3m)

| symmetry = P{{overline|4}}3m

| unit cell =

| color = Brown to black, greenish black

| habit = Aggregates

| twinning =

| cleavage =

| fracture = Uneven

| tenacity = Brittle

| mohs = 3.5

| luster = Resinous to semimetallic

| refractive =

| opticalprop = Isotropic

| birefringence = N/A

| pleochroism = Non-Pleochroic

| streak = Dark grey

| gravity = 8.928 calculated

| melt =

| fusibility =

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| diaphaneity = Subtranslucent to Opaque

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| references = [http://rruff.geo.arizona.edu/doclib/hom/gananite.pdf "Gananite"], Mineral Data Publishing, 2005, accessed 16 December 2010.[http://www.webmineral.com/data/Gananite.shtml Gananite Mineral Data], accessed 16 December 2010.

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Gananite ({{zh|s=赣南矿|t=贛南礦|p=gànnánkuàng}}) is a rare bismuth fluoride mineral form of bismuth trifluoride with a general formula of BiF₃.[http://www.mindat.org/min-1646.html Gananite], MinDat.org, accessed 16 December 2010. Gananite is an isotropic mineral that belongs to the space group P43m. This means that gananite does not show any colors in cross polarized light, because when polarized light passes through it, it does not split into two perpendicular rays. In other words, because gananite is an isometric mineral, it does not exhibit double refraction. Moreover, this tells us that this mineral is not birefringent.Jambor, J. L., Burke, E. A., Ercit, T. S., Grice, J. D. (1988) New mineral names. American Mineralogist, 73, 1492-1499. Its color in plane-polarized light is blackish-brown, and it does not show pleochroism.