Microwaving mystery mug

I have an Edward Gorey design Mystery mug, the kind that changes when you pour hot liquid into it so hidden figures are revealed. I know you're not supposed to run that sort through the dishwasher, but can't remember if it's okay to microwave them. Does anyone know? In the morning we boil water in a kettle, but when I just want a cup of herbal tea during the day, it's faster and easier to microwave it. (I think it's more energy efficient too, but I don't know for sure.) Of course I have other mugs I can use, but I just wondered.