Store Rønsten is a giant rock at 54 tons. It is laying in low tide in the reef between Kalø Slotsruin and Vrinners Hoved with other big rocks of 3 to 9 tons. Almost dried out at low tide, on with the waders or long wellington boots. These reef rocks are often used as lay-bys for the seabirds, especially gulls and the great cormorant, reef and rocks often also to seals. Aarhus Stiftstidende joined Jens Reddersen, when he measured the rock.
The rock is dark granite with big rectangular grains. The location suggests that Store Rønsten, together with other rocks, has melted out from the sole on the Kalø Vig-glacier. Alternatively it is remnants of moraines that have been pushed away by the ocean.
B: 56.265736° L: 10.474894°