Giant crystals are the heaviest, most valuable finds in Mine a Mountain, and they do not appear by chance while you dig. They come from detonating a Mythic-tier bomb inside high-rarity rock while the right runes are active on your plot. Get that combination wrong, and you either spawn small crystals or run out of backpack space before you can carry them home.
Quick answer: Place the Preservation, Detonation, Colossus, and Excavator runes on your plot, raise your carry weight to at least 30,000 kg, then detonate an Agony Bomb inside a thick section of the Legendary or Mythic zone. The blast fills the crater with giant Legendary and Mythic crystals.
Why the Agony Bomb is the only reliable source
Regular mining rolls crystal size independently for each crystal, and outside of Mythic finds the odds are stacked hard toward small pieces. The Agony Bomb bypasses that grind. It is a Mythic explosive that tears open the mountain and drops only Legendary and Mythic crystals, which are the richest pool in the game.
Size sits on a separate scale from rarity. The playable size classes top out at Giant, which covers 200 kg up to one ton. The truly enormous classes above that, Colossal, Titan, Leviathan, and Behemoth, are not rolled directly. Crystals grow into them through mutations, which is why size-up effects matter so much on an Agony Bomb spawn.
The four core runes to place first
Runes are timed buffs you drop on your base plot. For giant crystals, four work together to make a single detonation produce more crystals, bigger crystals, and a wider crater. Place Preservation first so everything else you set down afterward lasts twice as long.
| Rune | Effect | Boulder source |
|---|---|---|
| Preservation | Slows all rune timers by 50%, doubling active duration | Rimeveil (Epic) |
| Detonation | Bombs spawn +40% more crystals | Gildrite (Rare) |
| Colossus | +68% chance for crystals to size up toward Giant | Nocturnite (Legendary) |
| Excavator | +30% bomb blast radius | Nocturnite (Legendary) |
Runes drop from Boulders mined deep inside the mountain, and each Boulder type needs a matching pickaxe. Higher-rarity Boulders can also drop the lower-tier runes, so a Nocturnite Boulder, broken with The Terminus, can roll any of the ten runes in the game. If you pull duplicates, merge them to extend their effect time. The one exception is the Luck Rune, which you stack by placing multiples instead of merging.
Three optional runes add value on top of the core set. The Weight Rune doubles your carry capacity while active, the Fortune Rune raises crystal sell value by 50%, and the Luck Rune increases your plot luck for better mutation odds.
Getting Agony Bombs without overpaying
The Agony Bomb rarely sits in stock. Buying it outright costs 1,200 Robux, but there is a cheaper route through the shop’s restock button. A restock runs roughly 44 Robux and frequently drops several Agony Bombs into stock at once, priced around 600 million in-game cash each. Players repeating restocks report picking up three bombs for close to 500 Robux total, well under half the direct price.
Buy in bulk when you can. Having multiple bombs ready lets you chain detonations while your runes are still active, which is where the setup pays off most.
Raise your carry weight before you dig
Giant crystals are extremely heavy. A single one can weigh 20 tons, and the largest reach 42 tons. If your backpack cap is low, the game will block you mid-mine and force you to finish or drop what you started, leaving the biggest crystals on the ground.
Upgrade carry weight at the Upgrades stall to at least 30,000 kg before a run. If you are still short, place a Weight Rune on your plot to temporarily double whatever capacity you have. With the rune active, a 30,000 kg base becomes roughly 60,000 kg for the run.
Detonate the bomb in the right spot
Tip: Turn on the crystal filter in settings and set it to Mythic only. Lower-tier crystals disappear from view so you can spot and grab the highest-value pieces first before your backpack fills.
How to confirm it worked
A successful detonation leaves a wide crater filled with oversized crystals carrying size tags like [Titan], [Leviathan], or [Behemoth] and weights measured in tons. Hovering over one shows its tier, weight, cash value, and luck percentage. A Mythic crystal is always worth at least $1,000,000 no matter its size, and value climbs faster than weight, so the heaviest crystals sell for the most.
If the crater fills with small crystals instead, check the usual causes. The runes may have expired before you detonated, the rock section was too thin, or you detonated below the Legendary zone. Re-place the runes with Preservation first and move to thicker, higher rock.
Push luck higher for better mutations
Crystals from an Agony Bomb start around 36% base luck. A Poison Mutation, triggered by Poison Bombs, raises that to roughly 54%. Weather events layer on stronger mutations as well, and the Storm Rune doubles your chance of catching those weather mutations.
Back at your base, sort your haul by luck. Place the highest-luck crystals on your plot to permanently raise your passive luck stat, which improves future runs, then sell the rest to the Crystal Buyer for cash. Even large non-Mythic crystals can bring in billions per sale, so the routine of bomb, harvest, place, and sell compounds every hour when the mountain resets.
