"die striations" is not necessarily a numismatic term. There are a number of different causes of 'lines' on coins.
1. Inproper Alloy Mix - slightly different concentrations of differing elements in planchets can cause pinstripes in the color of the resulting coin. Often called a "wood grain" effect.
2. Die Gouges - often singular but can come in clusters or groups. They show as raised, often straight lines on the resulting coins.
3. Die polishing - Very thin raised lines on coins. Same basic idea as die gouges except much thinner and usually many more of them. Caused by using an abrasive instrument to remove unwanted problems from dies.
4. Die flow lines - disturbances in the smooth field of the die that show as thin lines radiating outward from the center of the design. The cause of luster on mint state coins, these lines develop on the die as molecules of steel break free from the die's surface and radiate outward much like sticks drawing lines in mud. Heavier die flow lines indicate worn dies.
5. Die cracks - Jagged, sharp lines that are raised on the coin and follow the pattern of cracks in the die that develop from design weakness. These can best be described in imagining yourself pouring mud out on a cracked sidewalk, allowing it to dry into dirt, then peeling the entire piece of dried dirt off the cracked sidewalk. What you would have in your dirt is a raised line that exactly follows the pattern of the crack in the sidewalk where the mud filled in the crack.
6. Lamination or delamination - caused by impurities in alloy mixed coins that allow layers to flake off the coin and separate. Result is that part of the surface of the coin literally peels back from the coin (and sometimes comes off altogether).
7. Environmental exposure - Many different things from holders to wrappers to simple exposure to the sun can cause stripes or bands of color on coins.
8. Whizzing - a method of hiding problems on coins that causes many very small scratches on the affected coin. Novice collectors often mistake these for mint state coins with die flow lines (causing luster).
There are others, but these are the most common causes (and terms) for 'lines' on coins.
Posted 12/03/2011 10:42 am
