[PBodyGT87]

if what is on the site is legit, and well, i don't know if trust a site titled "beverlytang.com" i would imagine it would crack, or mostly chip. they are saying it's not aluminum, but "alumina", in other words, a whole new susbtance, not a variation of aluminum. but i don't think it's really legit. I would assume those wheels are made out of some other material, like maybe a composition of lexan and other sorts, there are other acrylics and plastics that are rather strong.

don't trust everything you find on the interweb.

as for cracking and shattering, glass is really, technically, a plastic of sorts. glass is nothing more than a thin hard "skin" (on each face of the glass) that lays on top of a "softer" material. don't get me wrong, just cuz i say plastic, doesn't mean it's not strong or hard. anyway, when you break glass, if the "skins" are more elastic, the glass is liable to simply crack in a hairline, or, like that of a windshield, spidercrack but hold together, mostly maintaining shape, depending on the type of impact. but when the skin is less elastic, this is when you get the shatter effect, because the inner material cannot maintain shape without it. and much like the rubber of a popping balloon, the skin immediately retracts, releasing the inner material, and the glass falls apart into little pieces.