It has a slightly thick skin like an apple, semi-dry and grainy texture, with a slight apple flavor, about the size of a large grape, with one pit, reminiscent of that of a date.
These are jujubes.
We find them mostly in the Mediterranean region starting from like 500 m height(I have one of these tree in my garden).
You should just be careful if there is no holes made by worms in there, then you souldn't eat it. It's not poisonous but it will probably taste bad. To know, you bite it in the middle to check.
It grows during the end of august and start of september.
It's not too sweet unless it's dried up.
They are red when grown and green when not. Some are both: part green, part red.
Hope its not too late an answer but they are called Masawu here in zim and am having some right now. They have a slimish feel in the mouth sort of like okra slime but tasty sweet to sour depending on the tree. worms love them too so if you mind look out for them. If you are like me anything that eats fruit is edible.
It's a lotus, or to be specific: Diospyros lotus More commonly known as date-plum. (Hence the pit as you noticed).
If you taste them, they have a chalky texture with hints of sweetness. They usually have a great aroma and smell. They are also good dried with tea.