Tomb of the Nomads (Location)
A reasonably lucrative tomb in the Isolated Desert.
Peruse the entry area for stray lootables, including silica.
Loot the west room, then follow the stairs up east to a room with a broken wall.
Do note the warning beyond.
With that in mind, you can decide whether or not to take the treasures by the water here.
You should, however, dive into the water, to scoop up the scattered silica. Beside one such chunk, you'll find a rotted wooden wall you can smash.
Go ahead and smash it to reveal the ancient tablet.
Read it (still underwater) to gain an ability point and complete the location.