what is the chances of finding a sapphire
To obtain a Sapphire use the mine [ore] option in the mining tab. The chance of finding a gem is 0.5% and can later on be used for Jewelry. Increasing your Luck stat will further increase your chances of finding one (the developers did not give any information on how much your chances are increased, however). The quality of the gem will match the highest quality of the ore you are currently mining (referring to the fact you can cross 2 different quality layers in mining).