Sun Stone

A little of everything: damage, defense, crit, regeneration, melee speed and mining speed. No single line on it is large enough to build around, but every class takes something from it, which is why it ends up in loadouts that have no obvious reason to want it. The mining speed alone earns it a slot on building and ore hunting trips.

It shuts off at night, and a good share of the fights you would want it for happen after dark. Either accept that it is a daytime accessory and swap the Moon Stone in for the other half of the cycle, or stop swapping entirely and combine the two, which gives you the same package around the clock.

None of it stacks with the upgrades. Wearing this next to a Celestial Stone or a Celestial Shell wastes the slot, because the game only counts the effect once.