This fruit has a bit of prickly and rough skin. When I cut into it the inside was stringy like ginger and it smelled like ginger and a citrus fruit. The juice that was left on the knife was the color of iodine. The cut slice quicle turned brown. There is a big pit inside. Thank you.
Thank you for your reply. Almost a year later I know what I had in my hands. Never would have figured that a walnut starts out like that. If I had to guess I would have bet that its some sort of a citrus fruit rather than a walnut.
Sorry. Doesn't look like a walnut to me - that said, don't know what it is! My grandpa used to grow walnuts - the fruit is smaller and more oval than the fruit in your photo; the green skin of walnut is quite thin and will stain your fingers (hence, walnut stains used on furniture...).