Character for dice in Cantonese 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?
骰 http://www.cantonese.sheik.co.uk/dictionary/characters/3676/
  
  dice
  
  jyuping: /sik1/ ; /tau4 /
  
  Pinyin: /tou2 /
  
  Jyutping tau4 is literary reading ; sik1 is colloquial. The latter one is much more common in usage.


As you can see, 骰 in Mandarin has only one reading (tou2)

In Cantonese,  the literary (tou2) and colloquial reading (sik1) of 骰 are different.

色(color) and 骰(dice) are just homographs that share the same reading /sik1/

I have never heard any Cantonese read 骰 as /tau4/ in my life.