Wonder how small $500,000 can be? See Mariah Carey 18 Carat Diamond Necklace

This is how to make $500,000 look very small. Mariah Carey's boyfriend James Packer splash $500,000 on a yellow heart shaped diamond necklace for his sweetheart. Are you still wondering why she has those glowing smile on her face? Try wearing a $500,000 and tell me how it feels *winks*

The singer showed off her stunning new accessory on Instagram on Thursday, and not surprisingly was grinning from ear to ear.  Lets take a close look at the little but mighty piece ...

Mariah Carey thanked JP for "a new heart" ... right before she sang "Hero" that night.

She told the audience: 'I have a new heart tonight' as the crowd whooped and cheered.

Mariah continued: 'James is in my heart tonight.'