Clay between silts and clays based on the plasticity properties of the soil, as measured by the soils' Atterberg limits. ISO 14688 grades clay particles as being smaller than 2 μm and silt particles as being larger. Mixtures of sand, silt and less than 40% clay are called loam. Loam makes good soil and is used as a building material. Clay minerals typically form over long periods of time as a result of the gradual chemical weathering of rocks, usually silicate-bearing, by low concentrations of carbonic acid and other diluted solvents. These solvents, usually acidic, migrate through the weathering rock after
Rock Sand to his best position of second on the list of leading sires. On his four-year-old debut, Rock Sand ran against Sceptre again in June over the Derby course and distance in the Coronation Cup, a race which also featured the first meeting between Rock Sand and his contemporary Zinfandel, a colt whose engagements in the previous year's classics had been rendered void by the death of his owner Colonel Harry McCalmont. Zinfandel won easily from Sceptre, with Rock Sand third. Rock Sand avoided Zinfandel for the remainder of the season and was unbeaten in his remaining five races. He won