Is your stone perfectly flat so that water does not "pool" on the stone? When you put it on the lawn is there a slight slope, so the water doesn't catch in the stone? I ask this because I have a stone patio, and only a few of the stones actually have a very slight concave spot that collects water.

Have you had constant rain, and is the patio shaded?

thank you, gottagarden. The water isn't collecting on top
of the stone at all, the moisture is coming up from below where the stone dust is still constantly wet when we lift up a slab. We have had rain but this isn't the problem. It's a drainage issue, and now I think we have to raise all the granite slabs and try somehow to wick the water away with pipes and replace all the stone dust with sand...A job I was hoping to avoid as the granite pieces are large and heavy and the terrace is about 800 s.f. thanks for listening!