Schüllerite

Schullerite is an orange to brown phosphate mineral rarely found in volcanic fumaroles. It forms small blocky grains primarily of interest to micro mineral and volcanic mineral collectors.

No products were found matching your selection.

Information about Schullerite

Schullerite is a very rare sodium barium magnesium titanium silicate mineral belonging to the heterophyllosilicate family – a group defined by their layered silicate structures in which silicon tetrahedra are linked into chains and sheets in more complex arrangements than the standard mica or clay structures.

It is known from only a very small number of localities, is primarily a micromount, and is of interest principally to specialists in Eifel mineralogy and in the crystal chemistry of titanium silicates. It is one of several minerals from this tight cluster of Eifel volcanic quarries that was named for a living amateur mineralogist, continuing a tradition of honouring field collectors at this exceptionally prolific district.

It forms tiny dark brown to reddish-brown platy to prismatic crystals, typically of sub-millimetre size, often as inclusions or intergrowths within other minerals in the calcium-rich xenoliths of the Eifel volcanic district.

 


Uses and History

Schullerite has no industrial or gemological applications. It is collected as a scientific specimen.

The mineral was first described in 2011 by Rastsvetaeva, Aksenov, and Chukanov, in a paper published in Doklady Chemistry. The crystal structure was revised in 2013 by Sokolova, Hawthorne, and Abdu in The Canadian Mineralogist, which corrected the formula to Na2Ba2Mg2Ti2(Si2O7)2O2F2. It was named in honour of Willi Schüller (born 1953), a German amateur mineralogist and collector, specialist in the mineralogy of the Eifel volcanic district, and author of numerous publications on Eifel minerals – an acknowledgement of the enormous contribution that informed amateur collectors have made to the documentation of this extraordinarily rich locality.

The sole confirmed localities are in the Eifel volcanic district of Rhineland-Palatinate, Germany, specifically the Lohley and Kahlenberg quarries – the same compact cluster of volcanological outcrops responsible for schullerite, ternesite, willhendersonite, vandermeerscheite, and zeophyllite found elsewhere on this site. No occurrences are recorded from any other country.

 


Mineralogy

Chemistry
A sodium barium magnesium titanium silicate fluoride with the formula Na2Ba2Mg2Ti2(Si2O7)2O2F2 (revised 2013). Monoclinic. Member of the heterophyllosilicate family; related to lamprophyllite-group minerals.
Colours and Variations
Dark brown to reddish-brown; an iron-rich variant from the Kahlenberg quarry has been documented.
Streak
White
Lustre
Vitreous to resinous
Transparency
Translucent to opaque
Fracture
Irregular; platy cleavage
Tenacity
Brittle
Crystal habit
Tiny platy to prismatic crystals; sub-millimetre; often as inclusions in other minerals
Mohs hardness
3 – 4
Fluorescence
Non-fluorescent
Specific Gravity
3.8 – 4.0
Easiest testing method
Field identification is not practically possible given the sub-millimetre crystal size and complex chemistry. Confirmed Eifel provenance from xenolith material is the most useful contextual indicator. Definitive identification requires X-ray diffraction using the 2013 revised structural parameters.

Hazards and Warnings

No specific health risks have been formally recorded for schullerite. Mineral collectors should wash their hands after handling specimens as a matter of good practice.

Almost all rocks, minerals (and, frankly, almost all other substances on earth) can produce toxic dust when cutting, which can cause serious respiratory conditions including silicosis. When cutting or polishing rocks, minerals, shells, etc, all work should be done wet to minimise the dust, and a suitable respirator or extraction system should be used.

 


Translations

Arabic:

Hindi:

Portuguese:

  • Schullerita

Bengali:

Indonesian:

Punjabi:

English:

  • Schullerite
  • Schüllerite

Italian:

  • Schullerite

Russian:

  • Шюллерит

French:

  • Schüllerite

Japanese:

Spanish:

  • Schullerita

German:

  • Schüllerit

Korean:

Thai:

Gujurati:

Mandarin Chinese:

Urdu:

 


Further Reading / External Links