Aspects of this topic are discussed in the following places at Britannica.
...small mirror.) The edges of the mirror have a fine fibrous or misty texture, called the mist. Surrounding the mist are wider and deeper radial ridges, with slivers of glass lifted out. Known as the hackle, these ridges ultimately lead to crack branching. Fracture travels faster in a region that is under tensile stress than in a region of compression; severe compression causes the direction of...
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