Microplastic particles are becoming more and more common in aquatic ecosystems all over the world, and are a huge source of pollution within the environment.  Studies of the physical transport of microplastics are limited, and cross-material comparison has not been undertaken on a large scale.  We have compared the settling velocity and shape properties of two common microfibers: polyester (synthetic) and cotton (nonsynthetic). From these data, we can determine key differences between these two fibers.