Introduction

The Gemstone Crab is a recently introduced group boss in Old School RuneScape, found in Varlamore’s Tlati Rainforest. It provides a unique opportunity for players to train combat skills with minimal effort and no risk of being interrupted by others. This guide explains how to make the most of this boss for efficient, hands-off experience gains.

Quick Facts

  • Combat Level: 160
  • Size: 5x5
  • Aggressive: Yes
  • Max Hit: 1
  • Attack Style: Crush
  • XP Penalty: 87.5% (1 damage = 3.5 XP)
  • Immunities: Poison, Venom, Cannons, Thralls, Burn, Freeze
  • Slayer: Does not count towards Slayer tasks

Location

  • Where: Tlati Rainforest, Varlamore (south and east of Tal Teklan, and north of Kastori)
  • How to Find: The Gemstone Crab appears in one of three possible caves. You can ask Rerald at any of these locations for its whereabouts, or simply check each cave yourself—entering a cave will take you directly to the boss if it’s there.

Requirements

  • Gear: Equip your strongest setup for the combat style you wish to train.
  • Items:
    • Prayer potions (if you plan to use offensive prayers)
    • Stat-boosting potions (to increase your damage output)
    • Pickaxe (optional, for mining gem piles after the fight)
    • Gem bag (optional, to store more gems)
  • No quests or stat prerequisites required!

How It Works

  • The Gemstone Crab cannot be killed and has infinite health; instead of a health bar, a green timer above its head shows how long it will remain at its current location (10 minutes).
  • Up to 16 players can attack the crab simultaneously, and all damage dealt is counted for rewards.
  • After 10 minutes, the crab burrows underground, leaving behind a gem pile for the top 16 damage dealers to mine.
  • Each eligible player can mine three random unnoted gems from the pile.
  • The crab then relocates to another cave, and the process repeats. Entering the next cave will bring you to its new location.
  • Ruby bolts (e) always deal 60 damage when their special effect triggers.

Rewards

  • Top 16 contributors can each mine three random uncut gems:
    • Possible gems: opal, jade, red topaz, sapphire, emerald, ruby, diamond, or dragonstone
  • Bring a gem bag to avoid losing gems if your inventory is full, as excess gems will drop to the ground.

Why Train Here?

  • No competition: The boss is designed for group play, so you won’t be forced out by other players.
  • Consistent combat: You remain in combat for the entire 10-minute timer, maximizing your XP per hour.
  • Highly AFK: You only need to interact every 10 minutes, making it ideal for multitasking.
  • Minimal risk: The crab’s attacks are very weak (max hit 1), so most players will take little to no damage.
  • Efficient XP: Although each hit gives slightly less XP than normal (3.5 XP per damage), the lack of downtime and overkill loss means XP rates are still excellent—up to 120,000 XP/hour for high-level players.

Tips

  • Use a gem bag to efficiently collect and bank gems.
  • If you only want combat experience, you can skip mining and immediately follow the crab to its next spot.
  • Boost your XP rates by using the best prayers and potions available.
  • Once you know the three possible locations, moving between them is quick and easy.
  • Note: Cannons and thralls cannot be used here. If your inventory is full, mined gems will appear on the ground.

Summary

The Gemstone Crab is an excellent option for players seeking effortless, uninterrupted combat training. With simple requirements, strong XP rates, and a group-friendly design, it’s a great addition to Varlamore’s content for both casual and dedicated players.

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