Individual grains can be identified easily. This sample is medium sand . Individual particles can be visually identified but the shape and roundness of the grains cannot be determined without magnification. The material are loose when dry and form a moderately strong cast when moist. This sample is fine sand .
Individual particles are more difficult to discern by eye.
Determination of roundness and shape for these and smaller particles requires magnification. The sample feels slightly gritty when dry, it forms a strong cast when moist, but it cannot be rolled into a ribbon. This sample is very fine sand . The sample feels powdery to the touch with a slight gritty feel. Can be moistened to form a strong and easily molded cast.