Most collectors ignore the proliferation of typical die cracks, die chips and small die breaks found on modern coins because they rarely carry any numismatic value. However, searching them out and assembling them into what collectors call "Progression Sets" can be fun and educational.
A progression set of this sort starts with a coin representing the start of the crack(s) and ends with the latest stage the collector can find where the crack(s) has widened, progressed further into the die and/or developed areas where pieces of the die has begun to chip or break away from the face of the die.
Chuck Chichinski of Ohio recently went through some uncirculated rolls of 2008 cents finding a progression of interesting cracks on a series of coins all struck from the same die pair. His progression starts with two or three very faint die cracks that eventually develop die chips and at the end, a neat looking small die break.
He separated discernible differences between the coins numbering them from 1 to 31 with each stack of coins representing a point at which there was a slight change in the pattern of cracks or chips. For our purposes, I narrowed it down to just four coins that mark points at which the most discernible differences occurred.
Stage 1: Two die cracks run from the rim with one crossing through the upper right side of the "I" and the other running between the "I" and "C." Both converge at the left center of the "C" and continuing on diagonally through to the lower "C" and out into the field through and down the left leg of the "A" and out again into the field below the "A." Another die crack branches off from the midsection of the larger crack running through the "C" downward into the field.
Stage 2: About the same as Stage 1 except that pieces of the die are beginning to chip out and fall away to the left side of the "C" where the two parallel cracks converge to form a die chip.
Stage 3: Here even more of the die has chipped to the left of the "C" and the crack below the "C" as well as the crack running from the foot of the "A" has lengthened.
Stage 4: Here we see that the area between the two cracks running down from the rim has completely chipped out of the die and become a small die break. At this point the die probably would not have lasted much longer and would have been taken out of service if noticed.