Is this 2008 Oklahoma quarter pmd or are there streaks across the coin from the mint? Probably nothing, but I thought I’d ask the experts. Thanks!
There is some heavy toning/corrosion (dark areas). The streaks are roller marks made during the mint process.
It's not a common occurrence but they are found on almost all denominations. Here are planchet striations on a Jefferson.
The striations (lines) come from the rolling process for the material the planchets are punched from. The final thin material starts out as a very thick (inches) bar that is heated and sent through steel rollers (think old washtub with squeezing rubber rollers you great grandmother used) that progressively squeeze the material thinner and thinner until the desired thickness is reached. The steel rollers are not always perfectly smooth and leave tiny lines in the material. If you want to investigate more, look "up rolling" mill on the internet. Do not confuse these roller marks with striations (lines) that occur in the material due to imperfections in the mixing of the metals that make up the final material. These are commonly called "woodies" because of their wood grain appearance.
