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[stoner]

The popular name "sluňák" is used for a specific type of quartzite, which is evidence of intense weathering processes during the Tertiary period. These processes took place under a warm and humid climate typical of tropical regions. During this time, not only was there mechanical disruption of rocks, but also their chemical breakdown. This process released large amounts of silicon dioxide, which silicified surface sediments, particularly sands and sandstones. As a result, a solid surface crust formed, from which today, in various locations across our country, we find polished fragments known as "sluňáky."
Here is Geovlog from our czech locality :-) https://www.youtube.com/watch?v=AE9GMV1xOoI

[stoner]

next one

[Bob Carnein]

It looks good enough to eat!

[stoner]

Thank you :-)