help me for ID.

[Beni]

Please help me to identification.
I have seeds. This is gift from my friend in borneo. East borneo.
He call, fruit like Kapul, have white flesh, orange skin.
Taste sweet and sour.
Fruit smaller than Kapul. Inside of fruit not wood. Like mangoestana. If i look the seeds, like mangostana family.

[anaxel]

mussels ?