Really pretty opera song but what is the name?

This is an easy one to answer. The aria you are referring to is Recondita Armonia ( pronounced Wreck on deeta Ar moe knee a ) It is sung by Mario Cavaradossi ( tenor ) in the opera Tosca by Puccini. This is the tenor's first big aria in the opera.... his other big aria is in the third act and is called E Lucevan le stelle. Cavaradossi is a painter and is painting a portrait in a church of a woman who comes to pray everyday. In the aria he compares the portrait with a minature he carries in his pocket of Floria Tosca. The aria is available on many CD's - My favourite recording would be by Jussi Bjorling