When a new mineral is discovered, there is a thorough and lengthy process to confirm that it is indeed new and to describe its distinctive characteristics. This identification depends on verifying its crystal structure, which is usually done using X-ray diffraction of a single crystal of the mineral. This technique needs the crystal to be perfectly homogeneous and large enough to analyse. When such crystals aren’t available, atomic‑resolution transmission electron microscopy (TEM) provides an effective alternative.
Adelaide University researchers, A/Prof. Cristiana Ciobanu and Prof. Nigel Cook, have identified and structurally defined a new mineral by using atomic-resolution TEM data. Microscopy Australia’s TEM Platform Scientist, Dr Ashley Slattery at Adelaide Microscopy, Adelaide University, collaborated with the team to get the best results that show the mineral’s crystal structure as clearly as possible.
Transmission electron microscope image shows the relative positions of atoms (white dots) in crystals of ehrigite, where the larger, brighter dots are bismuth and the smaller dots are tellurium.
The new mineral, ehrigite, is named after the world-renowned, South-Australian-based BHP metallurgist, Dr Kathy Ehrig, in recognition of her contributions to metallurgy. The atomic-resolution instrument allowed the team to visualise the unique arrangement of atoms in a tiny sample of this new mineral, showing it was different to all other known structures. It is made up of bismuth and tellurium with the formula Bi8Te3.
Since ehrigite was accepted as a new mineral by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification, the same team has also used TEM to also officially define clogauite, and are now doing the same for two further new minerals, with applications to the Commission expected in 2026.
C. Ciobanu et al., The Canadian Journal of Mineralogy and Petrology 2024.
DOI: 10.3749/2400023
N. Cook et al., Mineralogical Magazine 2024
DOI: 10.1180/mgm.2024.46
A/Prof. Cristiana Ciobanu, Prof. Nigel Cook and Dr Kathy Ehrig with the transmission electron microscope at Microscopy Australia's Adelaide University Facility, Adelaide Microscopy.
May 5, 2026
