MILEY CYRUS Rockin' Her Diamond Engagement Ring!

Miley Cyrus has conquered country and pop music, but it looks like she's the new queen of rock ... as in her huge 3.5 carat diamond engagement ring.

With her hair pulled back, shades and a belly-baring cropped top, the newly engaged 19-year-old flashed her 18-karat gold bling as she arrived at LAX on Thursday morning.

Miley's "Hunger Games" fiance Liam Hemsworth, 22, popped the question on May 31st, and got the ring from ritzy celebrity jeweler Neil Lane.

No word on when the young lovebirds will actually walk down the aisle.