Hearthstones
A Hearthstone is a crystal of solidified Essence, typically the size of a chicken egg, that forms in the hearth-room of a Manse. They have a rating from 1 to 5, usually the same as and never higher than that of the Manse they are created by. If a character is attuned to a Manse and has been touching its Hearthstone for at least a full day (or placed it in the socket of an artifact they are attuned to for at least a day) then each time they regain their daily Essence they also gain an extra 2x rating Essence tokens, refreshing has no extra effect. These extra tokens are lost if they stop touching the Hearthstone or de-attune from the artifact (and can only be used while touching the artifact if in a socket) and only one person can benefit from a hearthstone at a time. If in the Manse the stone comes from this is replaced by the normal benefit of being attuned to a Manse.
If the hearthstone (of an attuned Manse) is in the socket of an artifact the character is attuned to then it also grants the character an ability they can use while touching the artifact. To determine what this power is and how to control it requires an hours close study of the stone by someone with both Occult 3 and Lore 3 and either a Charm like All-Encompassing Sorcerers Sight or a Lore roll with a difficulty of the Hearthstone rating.