Miley Cyrus -- Engagement Ring Is Back in the Picture

Miley Cyrus sent a message to her fans -- and possibly her MIA fiancé Liam Hemsworth -- by showing her enormous engagement ring is back where it hasn't been for a while ... on her hand.

Miley posted a photo of herself -- in a unicorn onesie, by the way -- prominently featuring her left hand weighted down by her diamond rock.

As everyone's heard by now ... Miley and Liam have allegedly broken off their engagement. He's been with family in Australia -- and she's been spotted all over town sans ring.