Namesake Minerals #8

Today’s post features the penultimate mineral in the mythological namesake series. Tapiolite comes from Finland and is named after a figure from Finnish folklore.


Tapiolite from Baixao de Laje Mine, Parelhas, Rio Grande do Norte, Brazil (image by Rob Lavinsky from wikipedia.commons)

Quick facts:

  • Oxide mineral
  • Found in granite pegmatites and alluvial deposits
  • Type locality: Kulmala, Sukula Pegmatites, Tammela, Southern Finland Region, Finland
  • Formula: (Fe,Mn)(Ta,Nb)2O6
  • Crystal system: Tetragonal
  • Hardness: 6-6.5
  • Density: 7.72g/cmfor Mn variety; 7.90g/cm3 for Fe variety

Well-formed tapiolite crystal, from Sundrum Mine, Galconda District, Minas Gerais, Brazil (image by Christian Bracke from

Tapiolite is a niobium and tantalum ore – these two elements are rarely found in mineral specimens. Tapiolite is the name of a mineral group which contains an Fe-rich variety called ferrotapiolite and an Mn-rich variety called manganotapiolite; the latter is more common. It has the same chemical composition as columbite and tantalite but these two minerals are orthorhombic. It’s rare to find tapiolite specimens with euhedral crystals shown in the picture on the left.

Tapiolite was named in 1863 by Adolf Erik Nordenskiöld after Tapio, an ancient forest god from Finnish mythology who had a lichen beard and moss eyebrows. He ruled over a forest called Tapiola and hunters would pray to him before a hunt. He had four children with his wife Mielikki (the goddess of forests and hunting) called Annikki, Tellervo, Nyyrikki, and Tuulikki. Tapio appeared in a book written by Elias Lönnrot called Kalevala. This book is a compilation of epic poems originating from an area in Russia and Finland called Karelia.



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