A small cube, about 3" on each axis, constructed of frosted/opaque white crystal. On all sides except one, the surface is smooth with a slight marble texture, corners slightly rounded over, and on the 6th side is an inset cap made of a dark bronzewood. Affixed to this wooden lid is a simple brass ring to allow the lid to be grasped. Removing the lid reveals nothing more than an empty interior. While the design might suggest it was carved there are no visible tooling marks. In very low light the cube gives a faint grey glow. 

The interior and exterior of this box has been found to have a fixed temperature of 72° Fahrenheit. 72.3791° F to be exact. No matter the environment it is placed in, the exterior will maintain this temperature. When exposed to extreme temperatures, such as inside a forge, it will rise above its native temperature and will emit extreme amounts of light in the process, but upon being removed from the heat it will quickly return to room temperature. No environment cold enough has been found to have any effect on the box. Items placed inside of the box become room temperature themselves over time, no faster or slower than would be normal. Outside of extreme situations, the box does not seem to allow any thermal transfer through its walls and hot/cold items placed inside can not be felt in the hand of the holder. The box is assumed to be of standard durability for a stone box, but has not been tested to that end. While quite durable in its own right, the bronzewood lid seems to be unimportant to its temperature-keeping function.

This item is of unknown origin, but the stone it is crafted from is speculated to come from a subterranean deposit that exits naturally at "room temperature" all year.