Earthern Bulwark is a fairly important (and popular) skill from the Druid skill tree that goes into pretty much every Druid build in Diablo 4, which is where the Aspect of Mending Stone comes in.
This legendary aspect improves the duration of the said skill to bolster your defensive capabilities. Furthermore, if you are using any other earth skills to kill enemies, you are going to replenish the barrier you get from Earthen Bulwark.
Hence, when facing large groups of enemies, you have a high chance of keeping up your barrier throughout the fight.
Aspect of Mending Stone location in Diablo 4
For the Aspect of Mending Stone, you need to overcome and complete all the objectives of the Sealed Archives dungeon in Diablo 4. The dungeon is found north of the Untamed Scarps area of the Dry Steppes region, as indicated through the map below.

The best way to reach the dungeon is to use the Jirandai waypoint located in the south of this subregion. This waypoint is crucial as it opens your access to several other dungeons like Charnel House, Inferno, Champion’s Demise, and Sirocco Caverns. Additionally, the same waypoint allows you to access the Temple of Rot stronghold in D4.
Make use of this waypoint and clear the dungeon to get Aspect so you can use it in your best Druid builds, as protection is a crucial ingredient for this class.
Aspect of Mending Stone builds in Diablo 4
You can use the Mending of Stone aspect with any defensive build in Diablo 4. One such build is the Pulverize Werebear Druid, which uses aggressive and defensive skills to improve your AOE attacks.
The Aspect of Mending Stone gives you an extra cushion in the defensive segment. The aspect allows you to absorb incoming damage through the more extended barrier.
It ensures that the defensive wall from the Earthern Bulwark stays intact for a longer period. You can catch your breath during this time and use your AOE attacks after the wall goes to drain the health bar of your enemies.
Moreover, you can also opt for the Landslide Druid build to utilize this aspect in Diablo 4. The build uses Earthern Bulwark as a defensive mechanism, and extra protection always comes in handy in combat.