From the dictionary, it seems that the word for "dice" in Mandarin is either "骰子", pronounced "tóu zi", or "色子", pronounced "shǎi zi".
In Cantonese, the character for dice is pronounced "sik1" (Jyutping), and apparently written "骰", according to the written Cantonese sources I can find, which is odd because something pronounced as "tóu" in Mandarin would normally be pronounced as "tau4" in Cantonese. Curiously, the character "色" is pronounced as "sik1" in Cantonese, so it would seem to fit better if "sik1" were actually written as "色".
Is there some connection between the Cantonese pronunciation "sik1" and the character "色" and/or the Mandarin pronunciation of "shǎi"? Or is it just some coincidence with no underlying connection?