Helaldi is a fishing town in the central Black Sea region where construction of a rubble mound breakwater is being planned. The construction of the breakwater requires good quality durable armourstone. Several laboratory tests are performed for the quality assessment of the two potential armourstone, namely, limestone and sandstone. The quality evaluation of the stones is done on the basis of CIRIA/CUR criteria, saturation coefficient, wet-to-dry strength ratio, and the rock durability index. The quality evaluations are then compared with the field performance of both rocks. Laboratory test results, durability assessments and field performance of the rocks indicate that the limestone is a good quality armourstone and it can be used for the breakwater construction. However, the sandstone is marginal to poor material with very poor field performance, and should not be used for the breakwater construction.