title: Béhierite
text: # Béhierite
  
  Béhierite is a very rare mineral, a natural tantalum borate of the formula $(Ta,Nb)BO_4.$ Béhierite is also one of the most simple tantalum minerals. It contains simple tetrahedral borate anions, instead of more common among minerals, planar $BO_3$ groups. It forms a solid solution with its niobium-analogue, schiavinatoite. Both have zircon-type structure (tetragonal, space group $I4_1/amd)$ and are found in pegmatites. Béhierite and holtite are minerals with essential tantalum and boron.
  
  Béhierite was named for Jean Béhier (1903–1965), who discovered the mineral in 1959, as a French mineralogist, active in the Service Géologique, on the island of Madagascar.
  
  ## Occurrence and association
  
  Béhierite occurs in granitic pegmatites in Manjaka and Antsongombato, Madagascar. Associated minerals are albite, manganese-bearing apatite-group mineral, lepidolite, elbaite or elbaite–liddicoatite, feldspar, pollucite, quartz, rhodizite, and schiavinatoite.
  
  ## Crystal structure
  
  Crystal structure of synthetic $TaBO_4$ was refined by Range et al. (1996). As béhierite is analogous to schiavinatoite, their crystal structures are expected to be similar.
  
  