Where do I find plain talisman/shiny talisman?

The game tells me I need a plain talisman/shiny talisman for rerolling my weapon's stats.

I understand that I have not found the shiny one yet because I haven't played Chaos 4 that much. ...but I have no idea how I should get the plain one because its description says it can be found on Chaos 1, 2 and 3. I have played those difficulties pretty often and I have never seen a single one.

Is the description wrong or is the chance that low?

Talismans come from the 2 pirate ship maps.

Thank you. I'll try those maps more often.

Also note - you can only reroll primary stats, so begin rerolls on a piece of gear with near perfect secondary stats. 

@Jaws_420 quote:

Also note - you can only reroll primary stats, so begin rerolls on a piece of gear with near perfect secondary stats. 

Thanks! I guess that one saved me some ressources. ^^