Stoneware mug handles in the microwave do not get hot. If you use a manufactured mug and the handle is hot, the mug is made of low-fire earthenware.
My stoneware mug handles are all hand pulled, not extruded. I always press my thumb into the top of the handle to give a nice thumb hold as you hold your cup.
Stoneware is safe to use in conventional ovens, convection ovens, microwave ovens, and is freezer-safe and dishwasher safe.