Anastasia Morfiadakis, National Rock Garden Steering Committee and Wolfgang V. Preiss, Visiting Honorary Research Fellow, University of Adelaide and Geological Survey of South Australia
Published in the National Rock Garden Newsletter No. 28, December 2024
In June 2024, a remarkable addition to the National Rock Garden collection was made with the donation of a 2.1-tonne block of Myrtle Springs magnesite, generously provided by A. & M.J. Musolino. Special thanks go to Mr. C.M. (Ric) Horn of Hornet Resources, the company’s consulting geologist, for his enthusiastic support and facilitation of this donation.
Magnesite (magnesium carbonate, MgCO₃) is a versatile industrial mineral essential for applications such as high-temperature furnace linings, lightweight alloys, and magnesium-based chemicals used in industries ranging from aerospace to medicine.
The Myrtle Springs specimen originates from the Skillogalee Dolomite, a 790-million-year-old formation in South Australia’s Adelaide Superbasin. At Myrtle Springs, magnesite appears as rounded fragments (1–3 cm) embedded in a fine-grained dolomite matrix. These features reflect its formation in shallow lagoons, where continental and marine waters mixed, separated from the open sea by natural barriers similar to modern Coorong dunes in South Australia. The rare conditions required to create sedimentary magnesite make this specimen a geological treasure.
Magnesite continues to play a critical role in emerging technologies, including magnesium batteries, lightweight alloys for electric vehicles, and materials for renewable energy infrastructure. The inclusion of the Myrtle Springs magnesite in the National Rock Garden highlights not only its historical significance but also its relevance to the modern world.
Mrytle Springs is located 30 km north west of Leigh Creek, a former coal-mining town in eastern central South Australia. In October 2024, the NRG Steering Committee arranged for Phoenix Trucking of Fyshwick, ACT, to transport the magnesite to Canberra. The specimen is now in temporary storage while funds are being raised for the construction of additional rock platforms and pathways at the new National Rock Garden site within the National Arboretum Canberra. Stay tuned for updates as the magnesite block takes its place among the nation’s most iconic rocks!
