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It would be easiest to describe a "pebble" as an extra-large tumbled stone. They are rounded stones that have usually been cut and polished from massive deposits or damaged crystals, and that are larger than the usual tumbled stones. They are less suitable for use in body layouts than palmstones or tumbles, but do make very comforting pieces to hold in the hands for healing or meditation, or to simply to leave on a table or shelf to enhance a space with their energies and beauty.