Wool is the warmest blanket material. Wool is a natural material that includes a crimp, which helps to hold in more heat than a material with an open weave. It also provides natural insulation.
A wool blend, a combination of wool and other materials, offers the warmth of natural wool without the roughness. Additional blanket materials that provide warmth and comfort are cotton, fleece, cashmere and chenille. Cotton is a breathable fabric that is excellent for multiple purposes and levels of cold weather. Fleece is a synthetic material that is often used for warm blankets. Chenille and cashmere are more expensive but finer fabrics for blankets.