DIRECT ANSWER

The short answer

For the best yield in 1.21.x, branch-mine in the Overworld around Y=-58 or -59. For fewer direct lava encounters, use Y=-53 or -54. Mine with iron or better; Fortune increases diamond drops, while Silk Touch preserves the ore block.

PREPARATION

Exactly what you need

  • Iron, diamond, or netherite pickaxe — required
  • A spare pickaxe, food, torches, and a weapon
  • Water bucket for lava control
  • Coordinates: F3 in Java or Show Coordinates in Bedrock
  • Optional: Fortune III for yield or Silk Touch to collect the ore block

Where to find or obtain it

  • Dimension: Overworld
  • The deepslate variant appears where diamond ore replaces deepslate, normally at Y=0 and below
  • Highest practical branch-mining yield: Y=-58 to Y=-59
  • More lava-conscious compromise: Y=-53 to Y=-54

EXACT METHOD

Step-by-step method

  1. Turn on coordinatesPress F3 in Java, or enable Show Coordinates in Bedrock. The Y value is your elevation.
  2. Descend safelyBuild a two-block-high staircase and never dig straight down. Reach Y=-58 or -59 for maximum yield.
  3. Cut a branch mineMake a two-block-high main tunnel. Add two-block-high side branches with two solid blocks between adjacent branches.
  4. Control lavaListen for lava, break forward blocks from a safe position, and keep a water bucket on your hotbar.
  5. Use the correct pickaxeMine with iron or better. Fortune III can drop up to four diamonds; Silk Touch drops the ore block instead.
  6. Expose the full veinCarefully open all six sides around the first ore. The vein may continue above, below, or behind it, with lava underneath.

SAFETY & EFFICIENCY

Mistakes and dangers

  • Wooden, stone, and golden pickaxes produce no ore drop.
  • Lava is common at deep levels; never dig straight down.
  • Fortune is random: four diamonds with Fortune III is a maximum, not a guarantee.
  • Move quietly in Deep Dark areas; natural shriekers can summon the Warden.
PLAYER-TESTED TIPS

Collect the vein with Silk Touch and break it later with Fortune III.

Place torches consistently on one side so the exit remains easy to follow.

Branch mining is predictable because diamond generation exposed to air is reduced.

Version notes

Checked for Minecraft Java and Bedrock 1.21.x. The modern ore distribution applies to 1.18+ terrain; old, already-generated chunks may differ.

Java Edition1.21.8Verified source data
Bedrock Edition1.21.8Mechanics may vary

Sources and verification

Facts are summarized and cross-checked; source pages remain linked for exact tables, edition differences, and future updates.

↗Minecraft Wiki — Tutorial: Diamonds↗Minecraft — Block of the Week: Deepslate↗Minecraft Wiki — Diamond