Crystallography365

Blogging a crystal structure a day in 2014

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Helen Maynard-Casely

Ekanite – a mineral that will amorphise itself

What does it look like?

The crystal structure of Ekanite. The green atoms are the thorium which supply the radioactivity that breaks down the crystal structure over time. Image generated by the VESTA (Visualisation for Electronic and STructual analysis) software http://jp-minerals.org/vesta/en/

The crystal structure of Ekanite. The green atoms are the thorium which supply the radioactivity that breaks down the crystal structure over time. Image generated by the VESTA (Visualisation for Electronic and STructural analysis) software http://jp-minerals.org/vesta/en/

What is it?

Ekanite is a very rare gem, found originally in Sri Lanka, that is an olive green/brown colour. Not only is it quite a rare gem, but it also does something very unusual – it destroys its own crystal structure. This is because ekanite contains thorium, an element that often has high levels of radioactivity. The energy from this is enough to break down the crystal structure, and turn the material into an amorphous material, a glass where the atoms are arranged with little long-range order. This phenomenon is known as metamictization, and does actually occur in another mineral we've featured – Zircon – when the inclusions of thorium are high enough.

Where did the structure come from?

The crystal structure of ekanite is #9004161 in the Crystallography Open Database.

Tags: mineral   radioactive   thorium   rare