The unity sand ceremony represents the flowing of two lives into a single stream.
There are hundreds of thousands, if not millions of grains of sand, and when poured together, can never be separated.
The blending of the sand represents the union not only of them but their friends and families as well.
The separate sands once poured into the unity vase can never be put back into their separate vases.
They are forever entwined just as the lives and loves of Bride and Groom.