Tapiolite Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_ Mn)(niobium.html"_;"title="iron">Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_manganese">Mn)( Nb,_tantalum.html"_;"title="manganese">Mn)(niobium.html"_;"title="iron">Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_manganese">Mn)(niobium">Nb,_tantalum">Ta)₂oxygen.html" ;"title="niobium">Nb,_tantalum.html" ;"title="manganese">Mn)(niobium.html" ;"title="iron">Fe,_manganese.html" ;"title="iron.html" ;"title="iron">Fe, manganese">Mn)(niobium">Nb, tantalum">Ta)₂oxygen">O₆] is a black mineral series that is an ore of niobium and tantalum. The tapiolite group includes tapiolite-(Fe) or ferrotapiolite and tapiolite-(Mn) or manganotapiolite.Mindat tapiolite group
/ref> Tapiolite-(Fe) is by far the more common of the two.
/ref>
/ref> The minerals have a submetallic luster and a high

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...

with tapiolite-Fe having a higher specific gravity (7.90) versus 7.72 for tapiolite-Mn. The mineral was named in 1863 after the forest god Tapio of Finnish mythology, and the original tapiolite material came from Sukula, Tammela,

Tavastia Proper Tavastia or Tavastland may refer to: * Häme (Swedish: ''Tavastland'', Latin: ''Tavastia'') * Tavastia (historical province), a historical province of the kingdom of Sweden, located in modern-day Finland * Tavastia (constituency), formerly Tavasti ...

Finland Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of B ...

. Tapiolite is very close to ''

columbite Columbite, also called niobite, niobite-tantalite and columbate [], is a black mineral group that is an ore of niobium. It has a submetallic Lustre (mineralogy), luster and a high density and is a niobate of iron and manganese. This mineral group w ...

'' and ''

tantalite The mineral group tantalite Fe,_manganese.html"_;"title="iron.html"_;"title="iron">Fe,_manganese">Mn)Tantalum">Ta2oxygen.html" ;"title="manganese">Mn)Tantalum.html" ;"title="iron">Fe,_manganese.html" ;"title="iron.html" ;"title="iron">Fe, manga ...

''. Those minerals have the same chemical composition, but different crystal symmetry

orthorhombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a r ...

for tantalite or columbite and

tetragonal In crystallography, the tetragonal crystal system is one of the 7 crystal systems. Tetragonal crystal lattices result from stretching a cubic lattice along one of its lattice vectors, so that the cube becomes a rectangular prism with a square ...

for tapiolite.P. Cerny et al. "The tantalite-tapiolite gap: natural assemblages versus experimental data" Canadian Mineralogist 30 (1992) 58
free download
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References

{{Manganese minerals Tantalum minerals Niobium minerals Iron(II) minerals Manganese(II) minerals Oxide minerals Tetragonal minerals Minerals in space group 136 Minerals described in 1863