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Home | The Ants: Underground Kingdom | Crystal Mine Guide

Crystal Mine Guide

March 15, 2026
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Quick Summary
  • Mystic Crystals are used in the Mine Store to buy advanced evolution resources.
  • Excellent Mines produce the most crystals but are also the most dangerous.
  • Normal Mines are safe but have the lowest production.
  • You receive 3 hours of protection after occupying a mine.
  • Players receive up to 10 free occupation chances per day.
  • A successful plunder grants 50% of the defender’s gathered crystals.
  • Using your daily occupation chances efficiently is critical for progression.
  • The Crystal Mine is one of the main free sources of Amp Crystals for unlocking T11 Assault Soldier Ants.

1. Mine Types and Crystal Production

There are three types of Crystal Mines, each with different risk levels and production rates.

Mine TypeProduction per HourMaximum (12h)Risk Level
Excellent Crystal Mine4,00048,000Very High
Rare Crystal Mine3,00036,000Moderate
Normal Crystal Mine1,80021,600Safe

  • Excellent Crystal Mines: These mines provide the highest crystal income, but are heavily contested and frequently attacked.
  • Rare Crystal Mines: A balanced option with good production and moderate risk.
  • Normal Crystal Mines: These mines cannot be plundered, but production is much lower.

Each player can only place one troop in the Normal Mine, making it primarily a safety fallback option.

2. Cave Troops

Crystal Mine gathering uses Cave Troops, which function similarly to your regular march troops.

The combat power and troop count are identical to your Anthill march formations, but troop composition does not affect mining speed or maximum capacity. Troops are only used to defend the mine from plunders.

Cave Troop Unlock Requirements

  • Cave Troop I: Unlock Crystal Mine + Pro Rally Center
  • Cave Troop II: Rally Center I
  • Cave Troop III: Rally Center II + Queen Level 25
  • Cave Troop IV: Rally Center III + Amplification System

Unlocking additional Cave Troops allows you to occupy multiple mines simultaneously, significantly increasing your crystal income.

Note: Cave Troops use your regular Soldier Ants. Fighting inside the Crystal Mine does not injure your troops. However, if those Soldier Ants become injured outside the mine, they will automatically be removed from your Cave Troops and must be re-added after they are healed.

3. Mine Status Indicators

The Crystal Mine interface uses colored tags to quickly show mine status.

  • No Tag: Empty mine
  • Green: Occupied by you
  • Blue: Occupied by an alliance member
  • Red: Occupied by another player
  • Purple: Occupied by someone who previously plundered you

Mines occupied by alliance members cannot be plundered by you, making them safe targets from friendly attacks.

4. Occupation and Protection Rules

When you successfully occupy a mine, your troops receive 3 hours of protection.

During this time:

  • No player can attack your mine
  • Your troops gather crystals safely

Once the 3-hour shield expires, the mine becomes vulnerable to plundering.

Gathering continues until:

  • The 12-hour gathering limit is reached
  • Your troop is plundered
  • You recall your troop manually

You can recall troops at any time and immediately receive the Mystic Crystals gathered so far.

5. Occupation Chances and Daily Limits

Each successful occupation or plunder consumes 1 occupation chance.

Daily free occupation chances increase as you progress.

  • Crystal Mine unlocked  → 6 Daily Free Chances
  • Queen Level 25 → +2 Daily Free Chances
  • Amplification System unlocked → +2 Daily Free Chances

Maximum daily free chances: 10

Free chances reset daily at UTC 00:00.

6. Paid Occupation Chances

You can purchase additional occupation chances using diamonds.

  • Maximum 10 extra chances per week
  • Weekly purchase reset: Monday UTC 00:00

Important rule:

Purchased occupation chances do not expire and can carry over to the following week. However, you can only hold a maximum of 10 additional chances at any time. To purchase 10 new chances each week, you must use the previous week’s chances first.

The diamond cost of additional occupation chances increases with every purchase, resetting weekly. The cost of each occupation chance:

  • 50 Diamonds
  • 100 Diamonds
  • 150 Diamonds
  • 200 Diamonds
  • 300 Diamonds
  • 400 Diamonds
  • 500 Diamonds
  • 600 Diamonds
  • 700 Diamonds
  • 800 Diamonds

The total cost of 10 weekly attempts comes up to 3,800 diamonds.

7. Plunder Mechanics

Plundering is the fastest way to gain Mystic Crystals.

Successful Plunder

If you defeat the defender:

  • You receive 50% of their gathered crystals
  • Your troop takes control of the mine
  • 1 occupation chance is consumed

 

Failed Plunder

If your attack fails:

  • No occupation chance is consumed
  • That mine enters a 5-minute cooldown for you
  • During the cooldown you may still attack other mines.

8. Mine Management Tips

To manage your Crystal Mine troops efficiently, it helps to understand a few important mechanics and interface rules.

Normal Mine Occupation

Occupying a Normal Crystal Mine does not consume occupation chances, making it a safe option for passive gathering.

Rare and Excellent Mines

Every time you occupy a Rare or Excellent Crystal Mine, it consumes 1 occupation chance, including when using the Quick Occupy feature.

Checking Protection Time

You can check the remaining 3-hour protection timer by clicking on the mine your troop is currently occupying.

Quick Troop Location

If you click the troop frame showing your first ant, the game will instantly move the camera to the mine where that troop is gathering.

Manual Collection

Mystic Crystals are not collected automatically.

If your troop finishes the 12-hour gathering cycle or gets plundered when no Normal Mine slot is available, you must enter the Crystal Mine interface and manually claim the crystals before sending that troop out again.

The game will require you to collect the gathered crystals before the troop can start a new gathering cycle.

9. Automatic Backup System

If your troop is defeated in a Rare or Excellent Mine, the game automatically attempts to relocate it.

If you do not already have a troop in a Normal Mine, the system will move your defeated troop to an empty Normal Mine to continue gathering.

If you already have a troop in a Normal Mine, the troop that just got defeated becomes idle.

10. Weekly Crystal Ranking

The Crystal Mine also tracks weekly crystal production rankings.

This leaderboard measures the total Mystic Crystals gathered during the week, combining crystals obtained through both:

  • Gathering
  • Plundering

While the ranking itself does not provide rewards, the real value of the Crystal Mine is the steady Mystic Crystal income used to purchase valuable items in the Mine Store.

11. What to Buy in the Mine Store

The Mine Store offers a variety of progression resources, including Amp Crystals, Insect Ascension materials, Pioneer resources, and Gene upgrades, as well as basic resources such as meat, leaves, wet soil, sand and honeydew. Mystic Crystals should be spent on items that are difficult to obtain elsewhere.

 

Highest Priority:

Amp Crystals

Required for upgrading the Amplification System, which unlocks T11 Assault Soldier Ants.

The Mine Store is one of the few reliable free ways to obtain Amp Crystals, making it an important source for progressing toward T11 troops.

If you want to understand how the Amplification System works and how to unlock T11 faster, check out our Amplification System Guide.

 

High Priority:

Insect Ascension Materials

  • Ascent Shell
  • Exotic Fodder

These are critical for strengthening your insects.

Pioneer Resources

  • Meteorite Crystal
  • Exotic Leaf

Used to upgrade the evolution level and ascent level of Pioneer Special Ants.

Gene Resources

These materials improve Gene upgrades, which provide powerful passive bonuses to your troops.

Strategic Tips

Attack Mature Targets

  • Since you gain 50% of the defender’s gathered crystals, plundering a mine that is nearly full provides far more value than attacking a new one.

Use a Shock Unit

  • Recall your strongest troop from gathering before the daily reset to perform any remaining plunders, then place it back into an Excellent Mine afterward.

Use All Daily Chances

  • Your 10 daily occupation chances are the main driver of Mystic Crystal income. Missing them slows long-term progression.

Balance Risk and Safety

  • Excellent Mines provide the highest crystal income, so ideally all four of your Cave Troops should gather there.
  • But if you cannot defend your mine and can’t monitor it regularly, Rare Mines could produce better overall results due to fewer attacks.
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