Today, Prince Williams and his fiancée Kate Middleton made their first official appearance together since announcing their engagement.

When he popped the question, Prince William gave Kate the same engagement ring that his father, Prince Charles, gave to his deceased mother, Princess Diana.

The ring is now a family heirloom and is the most precious piece in the royal family’s collection of jewels. Prince Charles paid $65,000 for it when he married Princess Diana in 1981.

Jewelry expert Michael O’Connor tells UsMagazine.com the same style ring today would be valued at about $150,000.

“It is very special to me,” William told the press at St. James’ Palace today. “It was my way to make sure my mother did not miss out on today and the excitement that we are going to spend the rest of our lives together.

The timing is right now, we are both very, very happy.”

This is not the same storybook romance that occurred between Princess Diana and Prince Charles. William and Kate’s 8-year relationship hasn’t exactly been Camelot. The couple split up at least half a dozen times over the last 8 years.

It seems like a foolish choice to give an unpredictable woman a precious piece of jewelry that holds such historic significance. Especially since it once belonged to his dearly departed mother.

What if Kate decides to break up with him again and refuses to give back the ring? Then what?