The desert is the biggest place in the whole game, you'll most likely end up getting lost if you wander around aimlessly.

- Right before the first village (x2). YOU HAVE TO TAKE IT FIRST ! Otherwise it will disappear. (2 units)


- After the first village, past the map (avoid tumblers by using the spotlight)



- After passing through the sand worms using the teleporter, past the first whale skeleton, just before the second one, there is a small path to the left



- From the previous screenshot, turn right, you'll see a small path in the mountains leading to a sandy area. The tetrerium is after the sand dune shown in the screenshot.



- Return to the big whale skeleton. To the right, there's a little settlement with 2 tumblers.



- From the previous one, head to the left of the skeleton, up a moutain path. (see the red little spot on the previous screenshot)
Sidenote : you can get to the second tower by climbing/teleporting up this path.



- Go to the direction pointed by the whale skull. Past some sand worms, then east. You can still see the whale skull from there.



- Back to the direction pointed by the whale skull. Keep going forward, past a wreck, you'll find another ore just before reaching a village



- Go back to the metal pillar you just past, then go to the west. Past a fish skeleton, you'll find another ore near a lone house



- Facing the house, take the path in the mountains. Just after beating a tumbler, look to your left, you'll see the second tower. Go in this direction, another ore awaits you not far from the road.



- Follow the main path to the tower, and activate it. Backtrack to see that a new portal has opened. Take it. Now you're facing a huge metal structure. Go right to find another ore under another structure.



- Go down the cliff, and head in a straight line.



- Facing the metal structure, turn your back and head forward in a straight line. You'll see giant insects fighting on your left. When the sand stops, you should see a path on the rocks. Climb and you'll soon arrive in a zone with a few dead trees. The ore is in the middle of this zone, near the first dead tree you'll encounter. The red light in the middle of the screenshot is the second tower



- Now, go aaaaaaaaall the way to the other side of the desert. Well, at least to the other side of the area patrolled by the giant insect. You'll find what you wish for just before a ship



- Next one is on another rock formation, not far from the previous one.



- Go to the other side of the ship to find another one nearby.



- Go to the metal structure, then head north until you find a sign. The ore is a little bit to the east. On the screenshot, the sign is over ion's head



- Pass through the village nearby (beware the tumblers !) and climb the path in the mountains to the west. You'll find it along the path to the left



- You'll arrive in a settlement. From here, go south-west, you'll find a zone with seeds and dead trees. The ore is nearby.



- Now take the south-east path to the third tower. The ore is near the tower



- Head down to the main village (the one with many tumblers), and follow the signs. The ore will be on the right along the path



- Continue to follow the path, you'll arrive at a plateau. Go east, past the graves, and head down to a new settlement. The last ore is to the south-east. ANI will tell you you collected every tetrerium ores in the desert. (Fact is : there's more)



- From the settlement, go north-east. You can collect a bonus ore on the way to a portal, in the middle of some ruins.



- Another ore is nearby, to the north-west from the ruins and the previous ore.



To exit the desert : take the portal, then follow the marker on your compass to the north until you find another portal taking you back to the forest.

- Follow you marker, ANI will detect it along the way. There is a scrap of metal nearby to the south.


- Along the way, under a metallic structure. Hard to miss.


- This one can be a bit tricky. After saving ANI (again) you can find it in a ravine. Either drop down at the cost of some damage, or get to the other side of the ravine, and take a path leading down, right into a stone maze. Follow the path and you'll reach the ore.

To navigate through the maze : From the start, go left. Follow the only path available. When you have the choice between going forwards or right, go right. The tetrerium is not far following this path.


- Follow your marker. The last ore is next to the portal. (3 units)

- Not far from your starting point. Go west, past the first shelter, next to a rock formation. Your starting point is near the rock formation on the left of the screenshot below.


- The second shelter is near a metal totem. You'll find an ore on top of it.


- Head north-west to find a third shelter, not far from another metal totem. From there, go south-west, it'll be on your right


- From the shelter, go east. It'll be at the bottom of a rock formation.


- Now go north-west to find a cave with a lot of tetrerium boxes. One of the boxes is on the other side of the machine shown on the screenshot. You'll get 10 tetrerium units.


- From the cave, go full east. If you let ANI in the cave, it should be at more or less 330 meters. Remember you can't pick it up without her, so call her when you find it.


- Go back to the cave, then go north. Follow the path of trees, the last ore will be there

- Inside the ship, in boxes. Hard to miss. (x3)


- To the left of these boxes, take the door and follow the path to a room with tetrerium boxes in it (x3)


- After talking with the ship AI, on your way to activate the terminals. (x4)


- In the room a bit further, with a terminal in it (x3)


- The ship cargo contains the last tetrerium units, granting you the achievement. (x14)


Side notes :
- If you already have 48 tetrerium units, the ship AI will NOT tell you about the ship cargo.
- If you followed this guide, you should end up with 72 tetrerium ores. Add it the first 2 you bring back to SISTER at the beginning of the game, and that means there are at least 74 ores in the game, despite the achievement counter stating there are 70.