Bomb Farm Gems

Bomb Farm has nine ritual gems used in the hero star ritual system. Each gem belongs to a compatibility group, and using three distinct compatible gems with a single hero attempts the next star. This page documents every gem and the rules that govern which combinations work.

If you are looking for the forge that upgrades equipment, that is the blacksmith face of Ritual. This page covers gems and hero starring, not gear upgrades.

The nine gems

Amethyst — A purple ritual gem used in the hero star system. One of the starter-compatible gems for early heroes.

Aquamarine — A blue-green gem associated with sustain and energy. Often used on Support-class heroes.

Citrine — A yellow gem often linked to gold and economy effects. Popular on Collector builds.

Diamond — The rarest and most versatile gem. Compatible with a wide range of hero types and often used in high-level starring attempts.

Emerald — A green gem tied to critical and damage effects. Common on Attacker heroes.

Oceanite — A teal gem often paired with mobility and speed effects. Used on heroes with movement-based abilities.

Roselite — A pink gem associated with recovery and House-related effects. Frequently seen on sustain and Support heroes.

Sapphire — A deep blue gem linked to defense and penetration. Used on heroes facing high-mitigation enemies in later worlds.

Topaz — An orange gem tied to timed stages and clock-related mechanics. Used on heroes for timed gates and speed-based strategies.

Bomb Farm: Idle Bomber Squadron RPG on PC (GameReed)

How hero starring works

The ritual system requires:

• One hero
• Three distinct compatible gems
• A gem compatibility check that validates the combination
• Gold cost (screenshots at launch showed approximately 250,000 gold per attempt)

The hero’s current star count determines which gems can be used. As a hero gains stars, the gem compatibility pool expands. The exact table of star-level gem requirements has not been published officially; we update this page when Stream On releases a gem compatibility chart.

Removing a hero from active duty also removes selected gems to prevent invalid combinations.

The verified ritual rule

One hero plus three distinct compatible gems equals one star attempt. This is the foundation of the entire ritual system. You cannot reuse the same gem three times in a single attempt. You cannot attempt a star on a hero with fewer than three compatible gems available.

Gem recommendations by role

Attackers — Emerald for damage, Sapphire for penetration against high-defense nodes in Iron Depths and beyond.

Collectors — Citrine for gold income, Amethyst for general compatibility, Diamond for versatility in late-game starring.

Supports — Aquamarine for sustain, Roselite for recovery, Diamond for expanding compatibility options.

Specialists — Depends entirely on the specific hero ability and role. Diamond is universally useful for specialists because of its broad compatibility.

Gem sourcing

Gems drop from Battle nodes and sealed drops, similar to equipment. The Lapidary Eye ability can upgrade the category of gem drops. Higher difficulty stages yield higher-tier gems more frequently.

Gold cost and economy

The launch-era gold cost for a starring attempt was approximately 250,000 gold. This is a significant early-to-mid-game sum. Do not attempt starring on a hero you will replace within a week. Star heroes you intend to keep on your primary squad for the long term.

Budget for starring when planning gold expenditure alongside equipment forging and skill tree nodes. The three sinks compete for the same resource.

Gem fusion and equipment stars

Hero starring is separate from equipment fusion. Equipment stars come from fusing duplicate gear pieces in the blacksmith face of Ritual. Hero stars come from gem rituals in the capsule face of Ritual. Do not confuse the two systems.

Equipment fusion details: Gear and Ritual. Hero starring details: Fusion.

When to star a hero

Star heroes when:

• They are your long-term squad member, not a temporary fill
• You have three compatible gems available and idle
• Gold reserves exceed your equipment upgrade budget
• The hero’s current star count is the only thing limiting their effectiveness

Do not star heroes when:

• You are still replacing Commons with Uncommons
• Your equipment on that hero is still +0 to +4
• You are broke after a big forge push
• The hero is a short-term Market candidate

Related pages

• Gear and Ritual — Equipment forging and fusion
• Hero Fusion — Hero rarity and starring details
• Skill Tree — Account-wide upgrades that complement gem builds