lol, i went to diabloii.net and they heard soem rumors that it would make a gem shrine appear in the game, or a gem drop
this was during the early stages of the game when nobody had much stuff, so one person said "I got 3 chipped gems, and before i had clicked the gem i had only gotten one, so i am 100 percent sure that the gem makes u get more gems from drops..... also i found a gem shrine, which i had never found before..." etc.