Glendonite 2

Glendon, New South Wales, Australia, about 4.5cm long.

Glendonites are a pseudomorph (a mineral that replaces another) of Ikaite, which has become Calcite. These unique, star-shaped formations can only form under icy, underwater conditions that are followed by a period of warming which causes the conversion of Ikaite to Calcite. I have posted my first glendonite 'cluster' here: [link] . These are singletons / twinned crystals.

In the Cretaceous, much of central and southern Australia was covered by a cold inland sea in which marine reptiles and ammonites lived. Their fossils can still be found in the outback. For much of the year, their world was covered in ice. As the glaciers melted and the climate grew warmer, Glendonites were created.

Scientists study glendonites because they are an indicator of climate change. Their presence and shape can indicate the sort of climate changes that occured in the past and may give hints about the effects of global warming today.


More information on Glendonite is available here:
[link]
Also, a very excellent resource on Glendonites:
[link]

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