schäferite

{{Short description|Rare vanadate mineral}}

{{Infobox mineral

| name = Schäferite

| category = Phosphate mineral
Berzeliite group
Garnet structural group

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| strunz = 8.AC.25

| formula = Ca₂NaMg₂[VO₄]₃

| IMAsymbol = Sfr{{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 = 496.57 g/mol

| system = Cubic

| class = Hexoctahedral (m{{overline|3}}m)
H-M symbol: (4/m {{overline|3}} 2/m)

| symmetry = Ia3d

| unit cell = a = 12.427 Å, Z = 8

| color = Red, orange-red

| habit = Octahedral crystals

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| cleavage = None

| fracture = Conchoidal

| tenacity =

| mohs = 5

| luster = Vitreous

| refractive = n = 1.96

| opticalprop = Isotropic

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| streak = Yellow

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| diaphaneity = Transparent

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| references = Ralph, Jolyon and Ida Chau, 17 August 2010, "Schäferite." http://www.mindat.org/min-7279.html. Accessed 27 September 2010.Barthelmy, David, 1997-2010, “Schäferite Mineral Data.” http://www.webmineral.com/data/Schaferite.shtml. Accessed 27 September 2010.

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Schäferite is a rare vanadate mineral with chemical formula Ca₂NaMg₂[VO₄]₃. Schäferite is isometric, which means that it has three axes of equal length and 90° angles between the axes.Verlagsbuchhandlung, E.S. (1999) Schäferite, a new vanadium garnet. Neues Jahrbuch für Mineralogie,1, 123-134. Schäferite is isotropic, meaning that the velocity of light is the same no matter which direction the light passes through.

It was named after Helmut Schäfer (born 1931) who discovered it in a quarry on the Bellerberg Volcano in Germany. It is found only in the Eifel Mountains volcanic area near Mayen, Laacher See district of Germany. It occurs within a xenolith in a leucite tephrite. It is the magnesium analogue of palenzonaite and is a member of the garnet structural group.