first are you talking about "loquats" which are sometimes called "Japanese plums" but are really a type of citrus , or are you talking about a type of plum?

Loquats aren't citrus. They're actually Rosaceae, so they're relatives of plums, though closer to apples, pears, quinces, etc.

If they're from actual plums, they should look like, well, plum pits, or, if they've been removed from the pits, little almonds. If the pits haven't been opened, you might want to pop them open...I know this helps with germination in peaches.