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By  Mark Pearce Keirissa Lawson 14 December 2023 2 min read

Key points

  • We use advanced instruments to look at the structure and composition of minerals and rock.
  • The research demonstrates the unexpected beauty and complexity found in minerals and geological formations.
  • Our findings underscore the importance of detailed geological research in uncovering hidden patterns and structures in the Earth's minerals.

It's that time of the year in Australia when the summer sun is blazing, and everyone is gearing up for a well-deserved break.

With festive decorations everywhere, our eyes are starting to see Christmas trees in unlikely places. It could be the end of year fatigue, but we bet you will see them too. How does it happen? Heat (and cooling) is a big part of why different minerals start to resemble festive forms.

Christmassy chromites

We love a warm Christmas, so we delved into the hottest lavas that have ever erupted onto Earth's surface.

Not only did we find nickel deposits fuelling our battery research, we also stumbled upon these enchanting Christmas chromites. These beauties formed when the lavas suddenly cooled over 2.5 billion years ago. High temperature followed by cooling causes amazing branch-like formations called dendrites. We used our micro-tomography instrument to create a three-dimensional image of their structure.

We think they look like miniature Christmas trees. Do you?

Three-dimensional imaging using X-ray CT scanning of a chromite sample from Leonora, WA, revealed curious Christmas tree structures.

Spot the Christmas tree in the mineral scale

We think of rocks forming as a slow process. And it is. But all things are relative. In a geological timescale, mineral ‘scale’ is near instantaneous.

Our next festive offering was discovered when looking at the build-up of mineral scale at a geothermal plant in New Zealand.

Geothermal power plants use hot water from deep in the Earth to make steam to generate power. The super-heated water contains a rich mix of copper, silver, and other metals that have dissolved out of rocks. When it forms steam, the metals precipitate as minerals like copper-iron sulphide, chalcopyrite.

With a bit of colour thrown in, a Christmas tree emerges in this copper-rich chalcopyrite scale sample.

This Christmas-tree structure was found in chalcopyrite which formed as a mineral scale from metal-rich hot water used geothermal plant in New Zealand.

Geology's sparkling holiday gift

And then there's the accidental festive magic we create ourselves. While preparing rocks for an entirely different experiment, a festive surprise emerged from the atomic mist.

While polishing rocks with a high-energy beam of argon, we found a bloom of acanthite form. This silver sulphide mineral is not very stable. When blasted with high energy beams, it vapourised and blossomed into a new festive bloom. We ended up with a gorgeous flower-like structure resembling a seasonal poinsettia. Or is it another Christmas tree? You be the judge.

A flower-like acanthite bloomed accidently when preparing a specimen for another experiment.

These minerals, shaped by extreme changes, whether natural or man-made, serve as a reminder that transformation can be beautiful. So, as we head into our summer holidays, let these minerals be a testament to the magic that change can bring, even in the scorching heat of an Australian summer!

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