It is our understanding that the unusual cone formations were formed from volcanic ash and debris spewed during an eruption of Mount Sahand being hardened and shaped by the elements over thousands of years. The formation of volcanic ash cones is local to Kandovan. Elsewhere, the ash blanketed the land. The existence of a high volume of ash and pumice far from Sahand's crater indicates that Mount Sahand erupted with a gigantic explosion in the distant past. Sahand's rock is about a million years old and the last eruption of Mount Sahand is thought to have occurred within the Holocene epoch, that is within the last 11,000 years. Today, Mount Sahand is an dormant volcano consisting of a crater lake encircled by twelve peaks, the tallest of which rises to a height of 3707 m. or 12,162 feet.
