> it stands to reason that bulk samples, visible to the naked eye, will not exhibit it to any appreciable degree. I don't follow. It only takes a single crack

> it stands to reason that bulk samples, visible to the naked eye, will not exhibit it to any appreciable degree. I don't follow. It only takes a single crack to split a sample into two macroscopic pieces. If a small crack begins forming, and likely to either heal or get worse, that seems to have obvious macroscopic effects.