1866 3 Cent Reverse Die Crack?

Thanks, any reason why early nickels were common for die cracks. Was this common for all early coinage due to the coining process or die material?

You missed the ones at 8 and 12. Yes they are die cracks. If the coin was higher grade (or if you look closer) you will probably find that there are other cracks running through the wreath joining these radial cracks.

Nickel is an extremely hard metal. The 75% copper 25% nickel isn't a lot softer. And if it is improperly annealed before striking it can tear the dies apart. The mint was not experienced working with nickel and it showed, poor strikes, lots of die cracks, and very short die life. While other denominations at the time were having die lives of 100 to 200 thousand coins, the Shield nickels had die lives at the beginning of the series of 10 to 15 thousand coins. By the end of the series 18 years later they had only worked their way up to around 23 thousand coins.