Americans do use the term lustre though. I know cos i've argued with them about lustre and uncirculated coins. It appears that for a coin to grade UNC in the US it has to have some lustre. But if you ask me UNC means just what it means, uncirculated! So what about a coin that has sat on a shelf for many years, has never been in circulation but was purchased from the mint, and has been removed from it's packaging? Now the example coin lets say has sat on the same shelf for the past 40 years and has reacted with the atmosphere, thus it is now toned and has lost its lustre. In a US sense it would now grade AU only. But hang on a minute the coin has never physically circulated and is as struck, but toned... so surely it's UNC? No?