It's a nice concept and I love it for that, but the poem as a whole would be much stronger if the stanzas held more flow.
For or example:
"It is the beauty of the heart
And such beauty cannot even be expressed even by Mozart"
could read:
It is the beauty of the heart
that cannot be expressed by even mozart.
By simple rearranging or cutting out unneeded words the poem keeps the flow and does not cause a reader to stumble. You wouldn't want your poem to be showing any obstructions to distract.
Still, you have a pretty good idea flowing here.
I hope I helped some.
