The three factors that influence the textures of igneous rocks are the speed of cooling, the silicate content, and the water content. The speed of cooling affects the texture because the faster the rate of cooling, the smoother the rock will be (finer texture, aphanitic). The slower the rate the rougher the texture (larger crystals, intrusive, coarse grained). Magmas with a high silica content tend to form long, chain-like structures before crystallization is incomplete, increasing viscosity (resistance to flow). Water helps dissolve atoms and promotes rapid formation of large mineral grains. The rate of cooling is the most important factor.