Crystal System: Tetragonal
Status of Occurrence: Confirmed Occurrence - 1st UK recording
Distribution: Rare
Chemical Composition: iron manganese tantalum niobium oxide
Chemical Formula: (Fe,Mn)(Ta,Nb)2O6
Method(s) of Verification: 'near Tremadoc' - XRD at the Natural History Museum, London (X-ray reference no. 3244F).

Chemical Group:

  • Niobates and Tantalates

Geological Context:

  • Sedimentary: allogenic (detrital)
  • Igneous
Introduction: tapiolite is the name given to a series with end members ferrotapiolite (iron-dominant) and manganotapiolite (manganese-dominant). Most specimens labelled as tapiolite are actually ferrotapiolite. Tapiolite occurs as an accessory mineral in zoned granite pegmatites and as a detrital phase within placers.
Occurrence in Wales: tapiolite was identified by XRD on a specimen labelled as 'near Tremadoc' submitted for identification at the Natural History Museum, London by D. Middleton. No chemical analysis has been performed, therefore it has not been determined whether this is ferro- or manganotapiolite.

Key Localities:

  • Tremadog, Gwynedd: a specimen labelled as 'near Tremadoc' proved upon XRD analysis at the Natural History Museum, London, to be tapiolite, but no further details are known.


There are no references for this specimen.