Do MediCrystal mats get hot to the touch when they heat up?

It depends on the temperature level. The mat gets hot to the touch if you put it at a high temperature.

It also depends on the model. The mats with crystals or stone disks covered by mesh fabric are hotter to the touch than those where the tumbled crystals are covered with a layer of luxury eco-suede or PU leather.

It depends if the heat radiates and dissipates or not. The mat surface gets much hotter when you are on the mat or if it is covered.