Was the Heart of the Ocean ever found?

No.

Have you ever watched the movie titanic?

They said that they can never find it..

Because it was still in Rose's hands.

It is now in the ocean, and at the bottom, no one has yet found it.

(suffice to say, it never existed at all)

The 'Heart of the Ocean' is fictitious.

It is based off of the Hope Diamond, but is otherwise complete myth.