The Thulecite Crown is head Armor that will absorb 90% of physical damage and has 1200 durability. When the wearer takes damage from an attack, it has a 33% chance to create a force field. The force field lasts for 4 seconds, preventing all damage from attacks (except for Fire) and granting stun immunity. While the force field is active, 5% of incoming damage is reduced from Sanity. The force field cannot occur more than once every 9 seconds. Unequipping the Crown will disable an active force field, even though the animation remains. The Crown's force field emits enough light to protect the player from Charlie.
Thulecite is renewable by killing the Ancient Fuelweaver to reset the Ruins and by feeding Amberosia to Dust Moths. Therefore, an unlimited amount of Thulecite Crowns can be crafted.
Tips
As it is clear from its perk, the Thulecite Crown is more suited for tanking enemies instead of kiting them.
The Crown is really useful when facing big groups of Mobs like Spiders, Hounds, and Birchnutters, as the force field will protect the players from being stunlocked.
The force field will protect from the special effects of enemy attacks, such as those of Frogs.
The Crown is a great armor for Willow, Maxwell, and Wigfrid since these characters can regain their sanity easily.
It is generally advised to also wear disposable body armor to increase the life of the Thulecite Crown. In Don't Starve Together, the Log Suit can absorb roughly 47% of already absorbed damage, effectively increasing the life of the Thulecite Crown from 840 to 1585.