"description=..." uses exact search, it looks for products that contain the string "14k pendant", and there's no such product. For example, this works: http://giftsniffer.com/store/search/...=round+pendant
To match words in any order, use "word=..." which translates to a full-text query in mysql: http://giftsniffer.com/store/search/?word=14k+pendant
However that doesn't work as full-text uses the minimum character limit set by MySQL. In your case it seems to be set to 4, not 3.
Another thing about full-text searches is that it will ignore words that are too short. That's why ?word=14k+pendant returns results with the word "pendant".
I would suggest decreasing your MySQL minimum word length limit if possible.