Rainbows & Radium

Chromite Nuggets (found in six colors: red, orange, yellow, green, blue, and purple) can be obtained by mining Chromite Ore (a sandstone variant found in the desert), with a chance to get 1-3 colors and 1-4 nuggets of each color. They can be combined in a Crafting Table (no specific pattern required) to make Raw Polychromite. This can be smelted into a Dull Polychromite Ingot, which can be combined with a Glow Inc Sac in a Crafting Table to create a Polychromite Ingot. Polychromite-Infused Sand has a chance to replace sand in the Desert, and will drop 1-4 Polychromite Dust. Putting four Polychromite Dust in the crafting table creates a Polychromite Ingot. 4 Polychromite Ingots can be combined with 4 Netherite Ingots to create Polychromium Alloy.

Radium Sludge is dropped from Uranium Ore (and it's Deepslate variant), and 4 can be crafted together to make a Uranium Ingot.

Deepsteel Plates have a chance to be found when brushing Suspicious Sand in a Quarry (A new structure that spawns in the desert).

Disc Fragments can be found by brushing the suspicious sand in Quarries. When 9 are combined in a 3x3 crafting grid, the new Music Disc "Below" by @T_en_M is created.

Deepsteel Paxels can be crafted like a pickaxe and axe combined, using 2 sticks and 4 Deepsteel Plates. They have the efficiency of iron tools and are effective on all blocks that can be broken with a shovel, axe, or pickaxe. They can also be used to strip logs and turn dirt blocks into paths. When upgraded with a Polychromium Upgrade Smithing Template and Polychromium Alloy in a Smithing Table, it becomes a Polychromium Paxel, which is similar but has the durability and mining speed of a netherite tool. Paxels can be enchanted with all enchantments that can be applied to axes, pickaxes, and shovels.

Polychromium Totems are made by upgrading an empty bundle with a Polychromium Upgrade and Polychromium Alloy. They are similar to a Totem of Undying, but have two charges each.

Polychromite Pearls can be crafted by surrounding an Ender Pearl with 8 Polychromite Dust. They have the "Infinity" enchantment, so you can basically use them infinitely. For balancing reasons, it has a 1 in 50 chance to break and turn into a regular Ender Pearl when used.

Polychromium Pouches are made by upgrading an empty bundle with a Polychromium Upgrade and Polychromium Alloy. They are small storage containers that have nine slots, like smaller shulker boxes, but can be opened by right-clicking, so they don't have the need to be placed and broken to access their contents.

Polychromite Experience Flasks can be crafted with 4 Bottles o' Enchanting and 5 Polychromite Ingots. When used, they throw 4 Bottles o' Enchanting at once.

Using 3 Deepsteel Plates in a row with two nether Quartz below and to the left of them, Deepsteel Keys can be crafted. They have no function until you add "bits" via an Artificing Table. There are 3 slots for bits, and they can accept any kind of Chromite Nugget, Iron Nuggets, Gold Nuggets, and Ghast Tears. That means that there are 729 possible combinations of bits. Keys can be used to lock, unlock and access Locked/Lockable Chests (See "Blocks/Storage")

Master Keys are only accessible via the Creative Inventory. If you forget the combination of bits on your key and/or lose it, and you want to access your Locked Chest, you have the option to give yourself one and open it.

Deepsteel Spears can be crafted by placing two sticks and a Deepsteel Plate diagonally across a 3x3 crafting grid. They deal 6 attack damage, have 0.9 attack speed, and have an extra two blocks of reach. Using a Polychromium Upgrade Smithing Template and Polychromium Alloy in a Smithing Table, you can create a Polychromium Spear, which deals 8 attack damage and has 1 attack speed. They can be enchanted with Unbreaking, Mending, Frost Aspect, and Weighted Shaft (See "Enchantments").

With a Deepsteel Plate and a String, you can create a Deepsteel Bomb. By default, they don't do anything when thrown, but you can add "charges" to them via an artificing table. There are 4 kinds of charges: Explosive (made with Gunpowder), Sonic (made with Echo Shards), Radioactive (made with Radium Sludge), and Magical (made with Dragon's Breath). Explosive Charges create normal explosions, Sonic Charges create sonic explosions that do not damage blocks and ignore armor, Radioactive Charges make an AoE cloud that prevents entities from healing, and Magical Charges damage entities in a radius, similar to how Dragon Fireballs work. The sizes of explosions/AoE clouds depends on how many charges of a certain type there are.

Polychromite Apples are crafted by surrounding an apple with 8 Polychromite Dust. They apply Regeneration II for 5 seconds and Absorption II for 2 minutes.

Polychromium Apples are made by upgrading a Golden Apples with a Polychromium Upgrade and Polychromium Alloy. When consumed, they grant Regeneration III for 5 seconds, Resistance for 1 minute, and Absorption III for 2 minutes.

If you use an Enchanted Golden Apple instead of a Golden Apple in the previous recipe, you will make an Enchanted Polychromium Apple. These apply Regeneration III for 20 seconds, Absorption V for 2 minutes, Resistance II for 2 minutes, and Fire Resistance for 5 minutes.

Fairy Bread is a common item to find in the Quarry (a new structure that spawns in the desert). Alternatively, you can craft it with a Bread and Polychromite Dust. When consumed, it heals 10 health (5 hearts) and has a 25% chance to apply the new Grace effect.

Using a Cooked Cod, Sweet Berries, a Golden Carrot, Polychromite Dust, and a Bowl, you can craft a Polychromite Platter. This instantly fills up your hunger and saturation bar, as well as granting the advancement "An Expensive Palette".

9 Chicken Nuggets can be crafted from a Cooked Chicken and a Bread. They are consumed in half a second and replenish 4 hunger (2 drumstick icons) and 0.2 saturation.

Uranium Ore and Deepslate Uranium Ore generate in veins of 2-3 blocks in all underground Overworld biomes. When mined with an iron pickaxe or better, they drop 1-4 Radium Sludge. If the pickaxe is enchanted with Condensing (See "Enchantments"), they instead drop 1 Uranium Ingot. If the pickaxe is enchanted with Silk Touch, they drop themselves.

Deepsteel Ore has a 25% chance to spawn each chunk. When they do, they generate in veins of 12-16. When mined with a Stone Pickaxe or better, they drop 1-3 Deepsteel Plates, unless the pickaxe has Silk Touch, in which case it drops itself.

Polychromite Ore and Polychromite-Infused Sand generate in veins of 1-6 blocks on the surface of the desert (i.e. first 15 layers). If the replaced block is Sand, then Polychromite-Infused Sand generates. If the replaced block is Sandstone, Polychromite Ore generates instead. When Polychromite Ore is mined with a Stone Pickaxe or better, it drops 1-6 colors of 1-2 Chromite Nuggets. If the pickaxe is enchanted with Condensing (See: "Enchantments"), it instead drops 1-2 Raw Polychromite. When Polychromite-Infused Sand is mined, it drops 1-4 Polychromite Dust, unless the pickaxe is enchanted with Condensing (See: "Enchantments"), in which case it drops 1 Polychromite Ingot.

Uranium Barrels are crafted with 8 Uranium ingots surrounding a Barrel. They have 84 slots (7 rows of 12). This is a severe lag hazard - do NOT break a full Uranium Barrel, and do NOT let creepers near ANY Uranium Barrels!

Lockable Chests can be crafted with a chest surrounded by 7 Deepsteel Plates and a Polychromium Alloy. They have 2 states, Locked and Unlocked. By default, they are unlocked, but when you use a Deepsteel Key on one (it must have 3 bits) while sneaking it locks the chest. Locked Chests can ONLY be opened by a player with a key in their hand that has THE SAME COMBINATION OF BITS in the SAME ORDER that the key used to lock it did. When mined, if the chest is locked, all items stay in the chest-item as if it was a Shulker Box, so breaking a Locked Chest will NOT be a viable way to steal items from it. If the chest is NOT locked, it drops itself and all items in in normally. The only way to unlock a chest is to use a Deepsteel Key that has THE SAME COMBINATION OF BITS in the SAME ORDER that the key used to lock it did (or, if you have access to commands or creative mode, a Master Key) on it while sneaking.

Stone Pedestals are crafted by making an "I" in the crafting table out of Smooth Stone, but replacing the top-center block with an Item frame. You can convert any pedestal to another kind of pedestal by putting it in the center of a crafting table and filling all adjacent slots with the correct material: Nether Quartz for a Quartz Pedestal, Gold Ingots for a Golden Pedestal, and Emeralds for an Emerald Pedestal. You can revert a pedestal to its stone form by using Smooth Stone.

Deepsteel Blocks, Polychromite Blocks, Blocks of Uranium and Blocks of Radium Sludge can be compressed from their respective items.

Radio Torches, Radio Lanterns, and Radio Campfires are crafted like their normal counterparts, but with Radium Sludge substituted for Coal/Charcoal. Food cooked by Radio Campfires applies the "Irradiated" effect for 30 seconds.

Radio Fire is a new variant of fire. It deals 8 damage and applies the "Irradiated" effect when touched. It can be created with a Flint and Steel on Radium ore, Deepslate Radium Ore, Blocks of Radium Sludge, and Blocks of Uranium.

You can craft Artificing Tables the way you would a Smithing Table, but replace the Iron with Deepsteel Plates. They can be used for adding charges to Deepsteel Bombs (See: "Items/Weapons") or bits to Deepsteel Keys (See: "Items/Tools").

The new Super TNT block behaves like normal TNT, but the explosion strength is doubled and an AoE cloud of the new "Irradiated" effect is spawned after the explosion.