If you're interested in buying or selling dolls, or finding the value of a doll, use the MEMBER DIRECTORY to find a NADDA dealer in your area and to link to member web sites. Your local library or bookstore is also a good place to find a price guide on antique dolls.
The intent of the standard is to define reasonable lippage from one tile to another. When a tile is warped but within standards, all of the corners cannot be set in the plane of the adjoining tiles. Accordingly, the tolerance for variation from tile to tile includes the actual warpage of the tile.
The relative hardness of glazed tile is an important issue that should be addressed when selecting a tile. Scratching the surface of the tile with different minerals at the same pressure performs the test and subjectively assigns a MOH'S Scale Hardness number to the glaze. The softest mineral used is talc, #1 if no scratch; the hardest is a diamond a #10 if no scratch.