Why does my pink crystal have heat on my hand? The same is true of cold weather.

Wearing it for a long time has heat. From the common sense of physics, what can't conduct heat? It's just fast and slow. Crystal feels cool because of its good thermal conductivity. When you wear it, if the crystal is big enough to dissipate heat quickly, you will find it cool! If you put it in your clothes, or if the crystal you wear is too small to dissipate heat, you won't feel cold!