Marzipan is a confectionery paste of ground almonds, sugar (and/or glucose syrup) and binders, worked into a smooth, pliable mass. Used to cover celebration cakes (notably Christmas and wedding cakes, under royal icing) and to model moulded fruits and decorations, its quality is graded by almond content — premium marzipan contains 40–50% almonds or more, while cheaper grades use more sugar and apricot-kernel substitutes. The high sugar and low water activity give a long ambient shelf life, though the oils can oxidise; it is packed airtight and stored cool. Because it contains tree nuts, allergen labelling is mandatory, and bitter-almond or apricot-kernel variants must respect amygdalin/cyanide limits.