Torbernite vs Metatorbernite, Lake Boga, Victoria

Mineral Matters #414

This week’s Facebook Mineral of the Week Group’s selected theme is uranium minerals.

One of the more common uranium minerals is torbernite. Well, maybe not. Maybe metatorbernite. There is still conjecture as to how many torbernites are actually metatorbernite once they are exposed to the atmosphere.

I will, without analysis, tend to label mine as metatorbernite if they are dull and opaque, and as torbernite if they are transparent. But apparently, the transparent ones can also be metatorbernite!

Here are a couple of specimens from Lake Boga, Victoria, Australia.

Below: Torbernite, Lake Boga, Victoria. Width of view 6.5mm.

Below: Metatorbernite, Lake Boga, Victoria. Width of view 5mm.