About

Minecraft contains over 800 unique block types across 20 biomes, each with distinct physical properties, blast resistance values, and crafting hierarchies. Choosing blocks for builds, challenge runs, or map design without a systematic randomizer introduces selection bias. Builders default to the same 15 - 20 familiar blocks, ignoring 90% of the palette. This generator uses a weighted random selection algorithm across 150+ blocks categorized by material type, biome origin, and rarity tier from Common (C) to Legendary (L). Rarity weights follow a geometric distribution where P(tier) ∝ 0.5^k, ensuring rare blocks appear infrequently but not impossibly. Block data reflects Java Edition up to 1.21. Note: procedural textures are approximations for visual reference only and do not replicate exact game assets.

Formulas

Block selection uses weighted random sampling. Each rarity tier k is assigned a weight w_k following a geometric decay model:

w_k = 12^k

Where k = 0 for Common, 1 for Uncommon, 2 for Rare, 3 for Epic, 4 for Legendary. The probability of selecting a block from tier k given n_k blocks in that tier is:

P(block) = w_kn_k ⋅ 4∑j=0 w_j

Where w_k = weight of the block's rarity tier, n_k = number of blocks in tier k. In uniform mode, all weights equal 1, giving each block equal probability P = 1N where N is the total filtered block count.

Reference Data

Block Name	Category	Rarity	Primary Biome	Blast Resistance	Version Added
Stone	Natural	Common	Overworld	6.0	Classic
Diamond Ore	Ore	Rare	Deep Underground	3.0	Indev
Obsidian	Natural	Uncommon	Overworld	1200	Classic
Netherrack	Nether	Common	Nether	0.4	Alpha
End Stone	End	Uncommon	The End	9.0	1.0
Ancient Debris	Ore	Legendary	Nether	1200	1.16
Deepslate	Natural	Common	Deep Underground	6.0	1.17
Amethyst Block	Crystal	Rare	Geodes	1.5	1.17
Sculk Shrieker	Sculk	Epic	Deep Dark	3.0	1.19
Cherry Log	Wood	Uncommon	Cherry Grove	2.0	1.20
Tuff Bricks	Building	Common	Underground	6.0	1.21
Copper Block	Metal	Uncommon	Overworld	6.0	1.17
Purpur Block	End	Rare	End City	6.0	1.9
Prismarine	Ocean	Uncommon	Ocean Monument	6.0	1.8
Crying Obsidian	Nether	Rare	Ruined Portal	1200	1.16
Moss Block	Natural	Uncommon	Lush Caves	0.1	1.17
Honey Block	Redstone	Uncommon	Bee Nest	0.0	1.15
Sponge	Ocean	Epic	Ocean Monument	0.6	Classic
Gilded Blackstone	Nether	Rare	Bastion Remnant	6.0	1.16
Beacon	Functional	Legendary	Crafted	3.0	1.4
Coral Block	Ocean	Uncommon	Warm Ocean	6.0	1.13
Emerald Ore	Ore	Epic	Mountains	3.0	1.3
Warped Stem	Nether	Common	Warped Forest	2.0	1.16
Calcite	Natural	Common	Geodes	0.75	1.17
Dripstone Block	Natural	Common	Dripstone Caves	1.0	1.17

Frequently Asked Questions

Rarity weighting uses a geometric distribution where Common blocks have weight 1.0, Uncommon 0.5, Rare 0.25, Epic 0.125, and Legendary 0.0625. This means a Common block is 16× more likely to appear than a Legendary one per individual block. Toggle to Uniform mode for equal probability across all blocks regardless of rarity.

The database includes blocks from Classic through Java Edition 1.21 (Tricky Trials update). This covers Tuff Bricks, Trial Spawners, and Copper Bulbs. Bedrock Edition-exclusive blocks are not included as there are negligible differences in the block palette between editions at the block level.

Yes. Use category filters to restrict to Building blocks only for palette challenges, or enable all categories for full randomizer runs. The history feature prevents re-rolling the same block. For challenge runs, the Legendary tier ensures rare blocks like Beacons or Ancient Debris appear at realistic scarcity rates matching approximate in-game generation frequencies.

Each block has a defined color palette of 3 - 5 hex values. A 16×16 pixel grid is drawn on a Canvas element. Pixel colors are selected from the palette using a deterministic noise function seeded by block name, producing consistent textures across sessions. These are visual approximations and not extracted from game files.

Blast resistance values follow the Java Edition technical data. Some blocks like Honey Block have 0.0 blast resistance (instantly destroyed by explosions), while Obsidian and Ancient Debris share 1200 blast resistance (Wither-proof). These values are the raw game constants, not the effective explosion protection which also depends on block position relative to the explosion center.