The caster further enchants an already created power stone, forming within it a latticework of energy that will direct the power of the stone toward producing heat when the item is active.

When activated, the stone will produce heat, as per the Warmth spell, for a cost of 1ep per hour.

The capacity of the stone is determined by the capacity of the Power Stone that was used to create it, so a powerful Heat Stone can last more than a day if fully charged.

Anyone touching the Stone may choose to channel energy into charging the stone. The use of the Fuel Pattern spell is unnecessary.

Further enchantment of this item may be possible using other spells, such as enchanting the stone to charge itself, or increased heat output.