Vote in Round 1 Match 9
It’s a pair of tiny minerals with unusual chemistry as hafnium-containing Hafnon battles with strontium/chromium-containing Putnisite.
Hafnon from Canada. Credit: David Hospital
The only known mineral with hafnium as its main component, hafnon is an analogue and in a solid solution series with 2023 champion Zircon. The small, resilient irregular crystals are colourless when pure, but often darken to orange-brown with impurities. This silicate is found in pegmatites around the world, and shares so many properties with zircon that the two can often be difficult to distinguish.
Putnisite from Australia. Credit: Henk Smeets
First recognized in 2017 in the Polar Bear Peninsula in Western Australia, Putnisite is the first mineral found that combines strontium and chromium.These tiny purple cubes are a rare hydrated strontium-calcium-chromium sulfate-carbonate with hydroxide ions. These waxy crystals have yet to be found outside Australia.
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