How to Get Aerogel in Subnautica — Recipe and Both Ingredients Explained

Aerogel is crafted at the Fabricator from 1 Ruby + 1 Gel Sack — that's the whole recipe, and both ingredients are mid-game finds: Ruby in the Grand Reef and Blood Kelp biomes (especially near thermal vents), Gel Sacks on the walls of deep caves. You need Aerogel for the Prawn Suit, Thermal Plant, Cyclops Fire Suppression System and Neptune Ion Boosters, so nearly every player hits the same two-item fetch quest around hour 10–15. This guide shows where both ingredients reliably spawn, how to farm Gel Sacks in a growbed, and exactly what the finished Aerogel unlocks.

Here's what you'll learn:

• The exact Aerogel recipe and where it's crafted
• Every Ruby spawn location, from easiest to deepest
• Every Gel Sack location and how to farm spores
• The full list of Aerogel recipes and quantities
• The fastest route to your first two Aerogel

Official resources: Steam store page · Official Subnautica Wiki — Aerogel · Official Subnautica Wiki — Ruby · IGN Subnautica page

The Aerogel Recipe

Craft it at the Fabricator (3-second build). There is no blueprint to find — the recipe is available from the start; you just need the ingredients. If you have neither, the fastest combined run is the Deep Sparse Reef / Blood Kelp Trench area, which holds both Ruby on the seabed and Gel Sacks on the trench walls within a few hundred meters of each other.

Per the official Subnautica Wiki — Aerogel: "Aerogel is a very light, porous gel in which the liquid component of the gel has been replaced with a gas. This results in a substance with incredible heat insulation. It is an advanced material and is crafted with the Fabricator."

Where to Find Ruby in Subnautica

Ruby (formerly "Aluminum Oxide Crystal" in the files) appears as white-blue mineral chunks with four stubby red crystal spikes, and it emits a faint glow at night, which makes night diving the fastest way to spot it. Confirmed spawn biomes:

Where to Find Gel Sacks in Subnautica

Gel Sacks are the edible flora that grows on deep cave walls. Confirmed locations:

• Blood Kelp Zone and Blood Kelp Trench — the most common spot; they hang on the trench walls in clusters
• Deep Grand Reef — on the cave walls near the Degasi base
• Lost River — "in abundance scattered around the edge of the brine streams" (official wiki)
• Underwater Islands Caves, Deep Sparse Reef — smaller clusters

Two things worth knowing before you harvest: each Gel Sack can be picked up whole (it's edible and doesn't rot) or knifed for spores (1 spore per strike, up to 3, destroying the sack on the third strike), and the spores grow into full Gel Sacks in an Exterior Growbed. Because Aerogel is used in several high-end recipes and Gel Sacks are rare outside deep regions, a growbed is the smart play — two trips to the Blood Kelp Trench give you a permanent supply.

What Is Aerogel Used For?

Verified recipes (official wiki crafting tables):

The big takeaway: the Prawn Suit itself needs 2 Aerogel, and the Thermal Plant needs 1 — so your first three Aerogel are spoken for before you even get to the fun upgrades. Collect 4–6 in one farm session and you'll never think about it again.

The Fastest First-Aerogel Route

1. Craft a Seamoth with the Depth Module MK1 (300 m) or MK2 (500 m) — stock is fine for Grand Reef, MK2 for the trench.
2. Swim to the Deep Sparse Reef / Blood Kelp Trench junction (drop a beacon).
3. Harvest 2–3 Gel Sacks from the trench walls (knife two for spores, pick up one whole).
4. Night-dive the Grand Reef floor for 2–3 Rubies.
5. Return to base, craft 2–3 Aerogel, and plant the spores in an Exterior Growbed.

That's a ~40-minute round trip that permanently solves the ingredient problem. While you're in the neighborhood, the Blood Kelp Trench also feeds into the Lost River — our Nickel Ore guide covers that route, and the Magnetite and Lithium you'll want for the same upgrades are in our Magnetite guide.

FAQ

How do you make Aerogel in Subnautica?

Craft it at the Fabricator from 1 Ruby + 1 Gel Sack. The recipe is available from the start; only the ingredients are gated behind biome progression.

Where do I find Ruby in Subnautica?

Grand Reef, Deep Sparse Reef, Blood Kelp Zone, Lost River, Bulb Zone, Dunes and Mountains Caves — most abundantly on and around thermal vents. Rubies glow at night, making night dives the fastest way to spot them.

Where do I find Gel Sacks in Subnautica?

On deep cave walls: Blood Kelp Zone and Trench (most common), Deep Grand Reef, the Lost River's brine edges, Underwater Islands Caves and Deep Sparse Reef. Pick them whole or knife them for 3 spores each.

What is Aerogel used for in Subnautica?

The Prawn Suit (2), Thermal Plant (1), Cyclops Fire Suppression System (2), Cyclops Decoy Tube Upgrade (1) and Neptune Ion Boosters (2). The Prawn Suit and Thermal Plant are the first two you'll craft.

Can you farm Gel Sacks?

Yes — knife a Gel Sack for up to 3 spores and plant them in an Exterior Growbed (or an Alien Containment). Two trips to the Blood Kelp Trench provide a permanent Aerogel supply.

Related Guides

• Subnautica Nickel Ore — Where to Find It
• Subnautica Magnetite — Where to Find It
• Subnautica Sea Crown — Where to Find It & Its Story Use
• Subnautica Walkthrough — Full Story Progression

Last updated: August 13, 2026.