Why is the temperature of the mat surface so low and why does it change so much?

If you keep your mat open without a protector pad on it, the heat is radiated and dissipates. As soon as you lie down on your amethyst mat or cover it, the temperature becomes more stable. When pre-heated, the crystals radiate heat very quickly. Cover it with a pillow and measure the temperature beneath it in 10 minutes, and you will be surprised by the difference.