Warkite
A scandium-rich oxide at the heart of the most refractory inclusions in carbonaceous chondrites.
Key facts
- Formula
- Ca2Sc6Al6O20
- Family
- Oxides
- Crystal system
- Triclinic
- First described
- the Murchison CM2 and Vigarano CV3 chondrites, 2013
Warkite was approved as a new mineral in 2013 from ultrarefractory inclusions in Murchison and Vigarano, and described in 2020. It is named after David Wark, an Australian cosmochemist remembered for the thin mineral rims, now called Wark–Lovering rims, that surround many calcium-aluminium-rich inclusions.
What it is
Warkite is an oxide of calcium, scandium and aluminium with a rhönite-type structure. Scandium and zirconium condense from hot gas at even higher temperatures than calcium and aluminium, so minerals rich in them are called ultrarefractory. Warkite is a key mineral of these rare inclusions.
Where it is found
It occurs in ultrarefractory inclusions in the Murchison CM chondrite and the Vigarano CV chondrite, together with davisite and other scandium- and zirconium-rich minerals.
How it is recognised
It is identified with a scanning electron microscope by its scandium-rich composition and by electron backscatter diffraction.
Did you know?
Wark–Lovering rims are layered coats only tens of micrometres thick, wrapped around many inclusions as their surroundings changed.
Scandium was predicted by Mendeleev before it was discovered in 1879.