Self-repairing seaming sand for seaming paving stones. In addition to crushed stone material, the seaming sand includes fully organic binders that prevent weed growth and reduce dust formation as well as the effects of erosion, minimizing the need for maintenance. The surface is water-permeable, but does not wash away with rain. Available in two grain sizes. The smaller grain size (Fescolock S) is suitable for seams less than 5 mm, and the larger grain size (Fescolock L) can be used for wider seams in the stone paving, such as in the seams of broadstones.