I'm a little bit unclear on hearthstones in Exalted 3rd edition. If a player buys just the Hearthstone merit (so no Manse, and no Artifact in which to socket the stone), what benefits do they get? I remember 1st Ed Hearthstones being really cool, but I can't quite figure 3e ones out. The rules - which I have read, but which are somewhat sprawling, so I may have just missed something - don't appear to be explicit. 

Some hearthstone descriptions explicitly mention socketing, while some don't - can I assume the latter type don't need it? 

Is there any kind of Essence trickle like in previous editions? In fact, I'm not 100% sure what the rules are on Hearthstone-essence-trickle even if socketed and/or accompanied by Manse ownership.