Geschichte: I found this rock during a beautiful hike in the Grimsel area. We drove to Lake Oberaar, hiked along the lake and then walked on top of the glacier which is located at the end of the lake. At the glacier's tounge, a small stream emerges from the ice and flows into the lake, forming nice sand and gravel banks. On the latter, I found this nicely shaped rock.
Geologie: This rock is a granite which formed about 300 million years ago in a magma chamber located within Earth's crust. There, the magma slowly cooled and solidified. After that, the rocks on top of it got slowly removed by erosion over millions of years. Today, the granites are at the surface and get eroded too by glaciers and rivers. Transport by water gave this rock its round shape.
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