Above is a classic example of a crippling flaw - the large fissure is part of a deep network of flaws that go almost to the chamber. It would have made a very nice plateau-topped bent egg..
Here's another throw-away, though more uncommon - a large crack was found inside of the briar block. This is one of the more time-wasting problems because it wasn't visible from within the chamber or from the block exterior, so the pipe was drilled and ready for rough shaping before the flaw appeared... all lost labor time that drives up the cost of those pipes which are usable.
This is a Ligne Bretagne stummel which was almost ready to go until it exposed a large pit fissure during the start of sandblasting. Blasting is a risky stage, as many such flaws can be uncovered by the process.
This was particularly annoying as a lot of work had been done on the pipe before the flaw appeared at the join of the shank and bowl. However, this one may have been for the best, as the shank extension did not come out as I had hoped either - it is blasted morta but the ring patterning was oriented poorly and it ended up looking rather silly.
This was the worst problem of recent memory, as the pipe would have been quite dramatic and it showcased extraordinary grain... unfortunately several deep pits appeared across the front and forced the whole piece to be abandoned after considerable work.