Single Tile - It would be recommended to use splints the same size as the tiles being sent (1/2" thick mdf or plywood works good but any thickness of a ridged material will help strengthen the tiles weak points). Wrap tile and splints very tightly with several layers of bubble wrap use packaging tape to keep bubble wrap tight. Place into a box surrounded with 2" or more of shock absorbing material.
Multiple Tiles - Stack tiles with thin foam 1/8" or less covering there entire surface in between each of the tiles than follow recommendations for single tiles.
Metro Marble Restoration can not be responsible for any tiles received broken from improper packaging.