9x12, acrylic on canvas paper
I was recently in Hilo, on Hawaii's Big Island. At my friend's house there was this beautiful starfruit. I found some fabric in the house to use as a backdrop and set up a lamp so the fruit was backlit (nothing like patient friends who let you use household items to jury rig a studio). I also bought a pad of canvas paper and borrowed brushes and acrylic paints from my friend. I think I did OK getting the glowing effect, and it was interesting to see how transparent some paints are and how opaque others are. But, wow, acrylics do dry awfully fast!
And here's the wikipedia star fruit page, which points out that it's closely related to the bilimbi.