Is this a cherry, or?

So, the kids brought these in the house claiming they are crab apples, but I'm pretty sure they're unripe cherries. They look like tiny apples on the outside and they're kind of hard like apples, so I can see why they would think that.... but inside they are red. I just need confirmation.

 

It looks like a plum to me.

 

Silver Surfer on another crabapple query mentioned "If it is a Prunus/plum it will have a single stone." Pic shows one stone (guessing you split the stone in half), hence ... it is a Prunus/plum. The "fleshy" part does look like a plum to me. A green thumb will need to confirm its variety.

 

Have them show you the source tree. And if you want it identified here post good illustrative pictures of growth habit and leaves.

 

I didn't really give a size reference, (and I'm hoping I gave enough context) but they are very small, like the size of grapes... the kids brought in a bunch that were even smaller than that, like the size of dimes. They were collecting them from the ground to eat them, and I panicked a little because I couldn't readily identify them. If they are plums, that's pretty neat! I've never seen plums that small before.

 

I'll do that tomorrow when they go back out to play.

 

We have a LOT of Prunus cerasifera planted as street trees here, purple leaved plums, some of which have a lot of (tasty) little fruits, most of which end up making a mess on the sidewalks.
prunus cerasifera fruits - Bing images

 

There are red fleshed crab apples and the slice does not show the seed very well, not exactly convincing of it being a plum or crab. Images of the rest of the tree or a cross section of the fruit should make it clear.

 

If you look at the blossom end of the fruit, it should be obvious if it is a pome or a prunus.