"Plain rice would be gluten-free. Most items with only one ingredient are safe, unless the ingredient is obviously a gluten source such as flour."
I unfortunately had a bad experience with rice. I had Unico long grain rice and OH boy I was in pain for days. I added other ingredients such as eggplants and lentils I had those both by themselves and was fine so rice had to be the culprit. It's such a pain because it's not listed anywhere on the packaging "may contain wheat, soy etc." I'm going to shoot them an e-mail about this see if there was some cross contamination.