Sand plays an important role in its application. Plaster sand for a plastered finish. Building sand for laying bricks or blocks. Riversand is mixed with cement stone and water for screeds. Plaster sand for a plastered finish. Building sand for laying bricks or blocks. Riversand is mixed with cement stone and water for screeds. Stone is produced by crushing larger rocks and is available in different sizes: 9.5mm, 13.2mm, 19mm, 26.5mm. Pebbles are generally used for covering driveways and garden landscaping.