Identify this fruit...

Hello friends!!!

Does anybody recognize this fruit...

I had shot this image from my phone Nokia 6300 few years back. Since then I am wondering what kind of fruit that was, even after that i had never seen this. I asked the vendor do let me know what is that fruit. Even the vendor didn't not know about this fruit. Also he offered me to taste is but I refused to taste, as it may cause unhygienic condition in me.

This is the piece.