A great example of an Archaic period Celt, from a private collection in Wood County, Texas. It measures 82.5 mms and was originally made in Eastern Greenstone.   This example shows the process stages of first Pecking and Grinding, and then polishing on the bit.   The bit had been resharpened to a steep angle.   Some axe/celts are also polished on the back end, but this is not needed on most every day user celts, as it only needs to fit the haft correctly and have the correct taper.    This style of celt was not lashed onto a wood handle, but fit into a hole in the handle with a one directional taper.  Hitting something with the celt only causes it to fit tighter into the handle, but a slight tap on the back side releases the celt for further sharpening.  This style was used throughout the world, and in the Americas throughout the Archaic period(as far back as 8,000 years ago) until very recent European contact.