Balanites...Sounds like a mineral, eats like a fruit
Actually, I'm only guessing at how it eats. I've never had it or even seen it. And I only know what I read about it in the following article:
African Fruits Could Help Alleviate Hunger and Bolster Rural Development (ScienceDaily)
One rather unfortunate legacy of colonialism (among many) is that Europeans' fruit crops to a great extent displaced the native crops in Africa and, to an extent, South America. North America's mostly held their own (strawberries, raspberries, blackberries, blueberries, cranberries, assorted are all mostly or partly North American in origin--the main fruit native to North America that hasn't hit it big that comes to mind is the Pawpaw) and were exported to the rest of the world themselves, and Asia and Europe had kind of shared a common pool of crop species for centuries. (I don't know enough about the native fruits of Australia to even comment, but I notice there aren't too many Australian species in the supermarket these days...)
The native fruits in Africa and South America are still around, for the most part, some on a small scale and some relatively common in the local market. But because they're unknown in the rest of the world, there's no great market and not that much money in them to prompt further cultivation and research.
Anyway, the linked article was prompted by the completion of the latest book in the Lost Crops of Africa series--Vol. III: Fruits. I read and enjoyed Vol. II: Vegetables, so I expect this to be a quality piece of work. And, because it's from the National Academies Press, the whole book is available online, as is the earlier Lost Crops of the Incas which has some cool info on South American species as well.