Old School RuneScape Guide

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Rubium splinters are stackable Sailing resources in Old School RuneScape used to make incendiary cannonballs for ship combat. They come from Rubium rocks and Rubium deposits inside the Charred Dungeon on Charred Island, with rocks giving direct splinters and deposits giving Rubium geodes that can be broken into splinters.

More Old School RuneScape guides, Sailing resources, and progression help are collected in the main OSRS hub.

What Rubium Splinters Are

Rubium splinters are stackable resources used to smith incendiary cannonballs for ship cannons.

They are tradeable, bankable, stackable, and mined from Rubium sources in the Charred Dungeon. Their main value is connected to Sailing combat, since incendiary cannonballs can burn targets when fired from a ship’s cannon.

Rubium splinters are not normal ore. They are more of a ship combat resource, and that makes their value depend heavily on how much players care about incendiary cannonballs. The item is also unstable by flavor, which is OSRS politely saying not to lick the spicy rock.

Rubium Splinter Detail	Info
Members	Yes
Tradeable	Yes
Stackable	Yes
Main Use	Smithing incendiary cannonballs for ship combat.
Main Location	Charred Dungeon on Charred Island.

How To Get Rubium Splinters

Rubium splinters are obtained by mining Rubium rocks at 48 Mining or by mining Rubium deposits at 68 Mining for Rubium geodes, then breaking the geodes with a hammer and chisel.

The direct method is mining Rubium rocks. Each Rubium rock gives a guaranteed 2 splinters, then may continue giving more until it randomly depletes. This is the lower level method and the simpler option for players who just want splinters without dealing with geodes.

The higher level method is mining Rubium deposits. These require 68 Mining and give Rubium geodes. The geodes are not stackable, but they can be broken into stackable Rubium splinters with a hammer and chisel. That means players can stay in the mine much longer by breaking geodes instead of banking constantly.

Method	Requirement	Result
Rubium Rocks	48 Mining	Direct Rubium splinters.
Rubium Deposits	68 Mining	Rubium geodes that can be broken into splinters.
Breaking Rubium Geodes	Hammer and chisel	Stackable Rubium splinters.

Rubium Rocks

Rubium rocks are mined at 48 Mining and give Rubium splinters directly.

Each Rubium rock gives a guaranteed 2 splinters. After that, the rock can keep producing more splinters until it randomly depletes. Player testing suggests the smaller Rubium rocks can be low intensity and may give around 4 to 5 splinters before depleting, although real rates can vary by level, gear, and how the final rates settle after release.

This method is better for players who meet 48 Mining but do not have 68 Mining yet. It is also simpler because there is no geode breaking step. The downside is that it does not have the same long stay potential as deposits, since the deposit method turns inventory space into stackable splinters as long as a hammer and chisel are available.

Rubium Rock Detail	Info
Mining Requirement	48 Mining
Output	Rubium splinters directly.
Guaranteed Yield	2 splinters per rock before random depletion checks.
Best For	Lower Mining levels and simple splinter gathering.

Rubium Deposits

Rubium deposits are mined at 68 Mining in the Charred Dungeon and give Rubium geodes instead of direct splinters.

Only 1 of the 2 deposits is active at a time. When the active deposit depletes, the other one replenishes. Once a player starts mining a deposit, it lasts around 4 to 5 minutes, then the next gathered geode causes the deposit to deplete.

Rubium deposits give between 10 and 100 Mining XP per successful mine and always give 1 Rubium geode. The geode can then be opened with a hammer and chisel for splinters, with the amount scaling by Mining level.

Rubium Deposit Detail	Info
Mining Requirement	68 Mining
Location	Charred Dungeon
Output	Rubium geode
Deposit Behavior	Only 1 deposit is active at a time.
Approximate Active Time	About 4 to 5 minutes after mining begins.

The deposit method is the stronger long session method because the geodes can be broken into stackable splinters. Bring a hammer and chisel or the whole point of the method gets much more annoying.

Rubium Geodes

Rubium geodes are mined from Rubium deposits and can be broken open with a hammer and chisel to receive Rubium splinters.

The important difference is that Rubium geodes are not stackable, while Rubium splinters are stackable. That means players should break geodes during the trip to preserve inventory space and stay inside the Charred Dungeon longer.

The number of splinters received from each geode scales with Mining level. Early player testing around high Mining levels suggests roughly 1,900 to 2,200 splinters per hour from deposit based mining, but these are early figures and should be treated as practical testing rather than final confirmed rates.

Rubium Geode Detail	Info
Obtained From	Rubium deposits.
Stackable	No
Opened With	Hammer and chisel.
Gives	Rubium splinters.
Splinter Amount	Scales with Mining level.

Charred Dungeon Location

Rubium splinters, Rubium rocks, Rubium deposits, and Rubium geodes are connected to the Charred Dungeon on Charred Island.

To access the deposits, players need to moor at Charred Island, which requires 60 Sailing. A rope also needs to be permanently attached to the dungeon entrance. The route through the dungeon passes through a multicombat area with aggressive red dragons and black dragons.

This is not the kind of mining spot where players should run in with nothing and expect a peaceful skilling trip. Bring protection, food, and enough attention to get through the dragon area safely. The mining itself may be low intensity once set up, but reaching the spot is not the same as clicking a rock beside Varrock.

Access Detail	Info
Island	Charred Island
Dungeon	Charred Dungeon
Sailing Requirement	60 Sailing to moor at Charred Island.
Dungeon Setup	Attach a rope permanently to the entrance.
Danger	Multicombat route with aggressive red and black dragons.

How To Make Incendiary Cannonballs

Incendiary cannonballs are made by using 10 Rubium splinters and 2 smithable cannonballs at an anvil to create 2 incendiary cannonballs.

The action takes 4 ticks and can be done in batches of 56, up to 28 actions per batch. When fired from a ship’s cannon, incendiary cannonballs have a chance to burn their targets. This makes Rubium splinters more useful for Sailing combat than for traditional Mining profit.

Recipe	Result
10 Rubium splinters	2 incendiary cannonballs
2 smithable cannonballs	2 incendiary cannonballs

The key ratio is 5 Rubium splinters per incendiary cannonball. That makes hourly splinter rates easier to understand. For example, 1,900 splinters would equal around 380 incendiary cannonballs before factoring in the needed cannonballs.

Best Rubium Method

The best Rubium method depends on Mining level. Use Rubium rocks at 48 Mining for direct splinters, then switch to Rubium deposits at 68 Mining for longer trips and Rubium geodes.

The rock method is better if the account only meets the lower requirement or wants simple direct gathering. The deposit method becomes better once 68 Mining is available because Rubium geodes can be broken into stackable splinters, which makes banking less of a problem.

Player Goal	Best Method
Lowest Requirement	Mine Rubium rocks at 48 Mining.
Longer Mining Trips	Mine Rubium deposits at 68 Mining and break geodes.
Making Incendiary Cannonballs	Use whichever method gives enough splinters for the 5 splinters per cannonball ratio.
Low Attention Mining	Use deposits once the account can safely reach the Charred Dungeon mining area.

At high Mining levels, deposits are the better long term method because the geode system lets players stay in the mine. At lower levels, rocks are the direct unlock and give a simpler path into Rubium splinters.

Is Rubium Worth Mining?

Rubium is worth mining if the goal is making incendiary cannonballs for ship combat, but it is not currently a standout Mining XP method based on early testing.

Early player reports suggest Rubium deposit mining can feel slow for XP, with some high level testing around 10,000 to 11,000 Mining XP per hour from deposits. Smaller Rubium rocks have been reported higher by some players, around the 50,000 XP per hour range without tick manipulation, but these are early player tested figures and may change as more data comes in.

The real reason to mine Rubium is the resource, not the XP. Incendiary cannonballs need splinters, and iron accounts or Sailing focused accounts may care more about that supply than raw Mining efficiency. Main accounts can also buy splinters if the Grand Exchange price makes mining them feel bad.

Worth It For	Verdict
Mining XP	Not a top method based on early testing.
Incendiary Cannonballs	Useful because Rubium splinters are required.
Iron Accounts	More relevant if ship combat supplies need to be self gathered.
Profit	Depends heavily on splinter price and demand for incendiary cannonballs.

Common Mistakes

The biggest Rubium mistake is confusing Rubium rocks, Rubium deposits, and Rubium geodes as the same thing.

Rubium rocks give splinters directly at 48 Mining. Rubium deposits require 68 Mining and give geodes. Rubium geodes must be opened with a hammer and chisel to become splinters. Mixing those up leads to wrong item prep, wrong requirements, and wasted trips.

Mistake	Better Play
Going to deposits below 68 Mining	Use Rubium rocks at 48 Mining instead.
Forgetting hammer and chisel	Bring both when mining Rubium deposits for geodes.
Forgetting Charred Island access	Have 60 Sailing to moor at Charred Island.
Ignoring the dragon route	Bring protection and supplies for the aggressive red and black dragons.
Expecting top Mining XP	Mine Rubium mainly for splinters and incendiary cannonball supply.

Quick Guide

Rubium splinters come from the Charred Dungeon on Charred Island and are mainly used to make incendiary cannonballs for ship combat.

Step	What To Do
1	Get access to Charred Island with 60 Sailing.
2	Attach a rope to the Charred Dungeon entrance if needed.
3	Bring a pickaxe, food, protection, and supplies for the dragon route.
4	Mine Rubium rocks at 48 Mining for direct splinters.
5	Mine Rubium deposits at 68 Mining for Rubium geodes.
6	Break Rubium geodes with a hammer and chisel to receive Rubium splinters.
7	Use 10 Rubium splinters and 2 smithable cannonballs at an anvil to make 2 incendiary cannonballs.

Final Blurb

Rubium splinters are mainly a Sailing combat resource, not a must do Mining XP method. Mine Rubium rocks at 48 Mining for direct splinters, or use Rubium deposits at 68 Mining for Rubium geodes that can be broken into stackable splinters with a hammer and chisel.

The deposit method is the better long trip option once the account can reach Charred Dungeon safely, while the rock method is the simpler lower requirement route. Rubium is useful because it feeds incendiary cannonball production, but the method is only worth camping if the splinters or cannonballs are actually needed. Otherwise, it is mostly dangerous red rock with extra steps, which is very on brand for Charred Island.

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