Ice Eggs in Finland

 

These ice eggs are very strange, and people are still not entirely sure how they form.   Complex interactions of many different processes.   These pics were taken on the shore of the Baltic, in Finland, last winter.  You need sub-zero temperatures, open sea that has not yet frozen over,  gentle small waves and an onshore wind.   So ice is forming along the shoreline, with ice crystals aggregating around small particles os sand or gravel.  The wavelets keep things moving, and the ball or egg shapes are a consequence of the ice eggs constantly knocking into one another and rounding off because of abrasion.