Star Boxes are awarded each time you earn a new Star in a Hidden Object Scene. You must open a Star Box to find out what is inside. What's in the box is always a surprise, but it is usually a selection of these things:
The fifth and final Star Box in each scene is a special 5-Star Box! These are especially hard to get, and so they should be more valuable, right?
You get one of these special 5-Star Boxes when you "master" a scene by getting the fifth Star. Like regular Star Boxes, you won't know what's in a 5-Star Box until you open it. But it MIGHT contain:
Lots of Coins
Lots of Energy
A few Diamonds
Rare materials like porcelain, copper, glass, terracotta, or marble
Exclusive Seasonal Set items (these are super rare!)
Note that 5-Star Boxes can also be purchased if you wish. But remember, you never know what is inside! Good luck!