You can "exchange" at major city blacksmiths with a "tuvala ore" in your inventory.

Also could drop from seasonal rift bosses

also a free pen tuvala ring & earring for lvling up your seasonal toon

Tuvala ore is no longer in the game, and all Tuvala enhancement materials have been condensed into "Time-filled Black Stone", which can be obtained through the main storyline quest, the Season pass, Rift Echos, regional grind zone quests, killing mobs on Season servers, and the "[Season Weekly] Stronger Tuvala Gear" quest.
Rift Echos will also sometimes provide Tuvala accessories. If you have Tuvala accessories or gear that you do not need, you can Press L -> Heat and melt down the unnecessary equipment into more Time-filled Black Stones. Although incorrect about the Tuvala ore, FriedShrimps is correct that you do exchange with major city Blacksmiths for any of the Tuvala accessories. If you hover over the Time-filled Black Stones, you will see a pop-up tool tip that gives further information. You can also do this for most other items in the game.


After completing certain tasks in the Season pass, you can recieve a free PEN Tuvala Ring & Earring, as well as a "Boiling Tides Black Stone". This stone will 100% guarantee enhancing a TET Tuvala accessory to PEN.