Strontium is a refined material in Subnautica 2 that you make by running celestine ore through a Processor. It feeds into advanced armor crafting and gates several mid-game upgrades, so most players hit a wall the moment they need it. The trick is that Celestine only spawns deep east of the Lifepod, well past the comfort zone of your starter gear.
What you need before crafting strontium
Celestine sits roughly 1,300 meters east of the Lifepod, near the Alien Ruins, at depths around 250 meters. You cannot reach it efficiently by swimming, and the route crosses a trench patrolled by a Collector Leviathan. A few pieces of gear make the trip survivable.
| Requirement | Why it matters |
|---|---|
| Tadpole submarine | Your first vehicle. Crush depth caps at 250 meters, which is exactly where celestine spawns. |
| Sonic Resonator | Required to break large celestine boulders. Hand tools will not work on them. |
| Processor | The base appliance that converts celestine into strontium. |
| High-capacity air tank (optional) | Useful because you swim out of the Tadpole to mine at the depth limit. |
| Tadpole depth module (optional) | Lets the Tadpole dive past 250 meters without taking hull damage. |
If you do not have the Tadpole yet, you need to scan three Tadpole fragments, unlock the moonpool blueprint, and build a base with a moonpool and vehicle fabricator. That path runs through the "Investigate the Tadpole Pens" mission and pulls in silver, sulfur, and gold along the way.
Where to find celestine
Celestine is a silver-blue ore that clings to rock walls and the seabed inside the alien biome east of the Lifepod. It only appears in this region, so do not waste time scanning shallow waters. Deposits yield 1 to 3 celestine each when broken with a Sonic Resonator.
The safest farming run starts at the Alien Ruins marker. Drive the Tadpole 180 meters northeast, then descend until your depth gauge reads 250 meters. Do not go deeper without the depth module or your hull will start taking damage.
Look back toward the rock wall. The first celestine deposit sits next to a visible underwater current. From there, follow the cliff edge west-northwest. The line of deposits continues along the wall and ends at a cave that holds two more large nodes. The full route gives you seven large celestine deposits with no aggressive fish in the area.
Because the Tadpole is parked at its crush limit, hop out, swim down to each node, blast it with the Sonic Resonator, scoop the ore, and return to the sub for oxygen before moving on.
Process celestine into strontium
Back at your base, drop celestine into a Processor. The recipe is fixed, and the output is straightforward.
| Input | Output | Time |
|---|---|---|
| 2x Celestine | 1x Strontium | 30 seconds |
The Processor is the same appliance you use for titanium ingots, copper ingots, and lead refinement. If you do not have one built yet, the blueprint costs 2 titanium, 1 mild acid, and 1 copper wire.
What strontium unlocks
Strontium is a gating material for late-game defensive gear and upgrades. The most direct use is Strike Armor, an advanced defensive module that demands processed strontium rather than raw celestine.
| Use | Notes |
|---|---|
| Strike Armor | Advanced defensive module. |
| Tadpole depth module | Removes the 250-meter crush limit on the Tadpole. |
| Modification Station | Required for tool and vehicle upgrades, including Tadpole power efficiency. |
| Bioscanner upgrade | Improves your scanner for advanced environmental analysis. |
Common reasons the recipe fails
If the Processor does not start, only a few things cause it. You either lack the second celestine, your base is not powered, or you are using the wrong appliance. Strontium does not come from the Fabricator or the Biolab, only the Processor.
If you smashed a celestine boulder by hand and got nothing, that is expected. Large deposits require a Sonic Resonator. Medium nodes can be cracked with the Scanner or Survival Multitool, but most celestine spawns as large boulders along the cliff walls.
Once you have a steady celestine route locked in, strontium becomes a renewable bottleneck rather than a hard one. Two trips to the Alien Ruins cliff line will usually stock enough ore to fully kit out armor and module upgrades before you push into deeper biomes.