Bukkit

The xLevel is calculated as following:

(Foundrate diamond * 10) + (Foundrate gold * 3) + (Foundrate Lapis * 10) + (Foundrate Iron * 1) + (Foundrate Mossy * 7)

If player broke less then 500 stones => xLevel divide in half If player broke more than 1000 stones => xLevel counts twice

The xLevel should never be over 100 => if so xray-using is used most likely