The wind crest is found behind the tiger statue. To gain it you will need the blue jewel. Once you do you can use it to unlock the back door and get out to the courtyard.
Resident Evil Directors Cut
The wind crest now takes the place of the star crest, it is located behind to the last painting in the art gallery. You'll need to solve a small puzzle to gain it.
Resident Evil Remake
You'll find the Wind Crest in the Researchers Rooms on the eastern side of the Mansion's second floor. After solving the puzzle with the bee and the hook you'll reveal this item. Later on in the game when you are outside, by using the Wind Crest on a panel that you'll find in the smaller graveyard, you'll be given the Moon, Sun and Star Crests. Examining the back of them reveals patterns which slot into the panel - revealing a 357 Magnum.