Firn is partially-compacte névé, a type of snow that has been left over from past seasons and has been recrystallized into a substance denser than névé. It is ice that is at an intermediate stage between snow and glacial ice. Firn has the appearance of wet sugar, but has a hardness that makes it extremely resistant to shovelling. It generally has a density greater than 550 kg/m³ and is often found underneath the snow that accumulates at the head of a glacier.