While infinite stones would be nice, the game very carefully tracks every stone you get and where you got it. You can see for yourself, open the menu, then click the little [+] icon next to the Chronos Stones (the buy page). Then click "Usage History" on the left. It shows every stone you've bought, gotten as rewards, gotten from daily mail, and every stone you've used, for the past 3 months. No way to trick CS, they're all done server-side and tracked.