I added the following entries to our glossary. Thanks to all who contribute.

Floating Roof: When a die is over-polished, the devices are often reduced in size, or in extreme cases, completely removed from the die. A Floating Roof is the name given when parts of the memorial building are polished away, making it appear the roof is floating in mid-air. See also Abraded Die, and No FG. Photo courtesy of forum member addictedtocoins.



Rockwell Hardness Test: A test done at the mint to determine if a planchet or die is of appropriate hardness. The test involves pressing a small metal ball into the planchet or die and measuring the depth of the resulting cavity. This smooth round or oval cavity can be sometimes seen on struck coins. Please visit this link for more information and photo examples. http://conecaonline.org/content/RockwellHardnessTest.html