Gloomsherds are pottery sherds from the Deeper and Darker mod, and they’re used to craft the 
Gloomslate Pot, a dark version of the Decorated Pot with Otherside patterns on its sides. There are nine of them, eight with a pattern and one plain 
Gloomsherd, and you’ll mostly find them inside fossilized 
Crystallized Amber.
They’re purely decorative, so you won’t need them for any gear, but they’re the only way to put the mod’s patterns on a pot. Gloomsherds and Gloomslate Pots were added in 1.4, so they aren’t in the 1.20.1 version of the mod, which stops at 1.3.3.
Obtaining
The main source is fossilized Crystallized Amber, which forms in the gloomslate columns of the Overcast Columns. Mining a fossilized piece without Silk Touch breaks it open, and there’s about a 2% chance for each of the 
Brittle, 
Temple, 
Ward and 
Wayfinder Gloomsherds to be what’s trapped inside.
| Gloomsherd | Crystallized Amber | Pot Mobs |
|---|---|---|
| Gloomsherd | No | Yes |
| Brittle Gloomsherd | Yes | Yes |
| Dark Heart Gloomsherd | No | Yes |
| Listener Gloomsherd | No | Yes |
| Snapper Gloomsherd | No | Yes |
| Temple Gloomsherd | Yes | Yes |
| Transmission Gloomsherd | No | Yes |
| Ward Gloomsherd | Yes | Yes |
| Wayfinder Gloomsherd | Yes | Yes |
The other five can only be dropped by the Anger, Fear and Sorrow Pots, which give one or two random Gloomsherds each when killed. These mobs don’t spawn naturally in 1.4.1, as no biome or structure is set up to spawn them yet, so outside of Creative those five sherds can’t really be collected.
Mining Crystallized Amber with Silk Touch gives you the block with whatever is trapped inside it, rather than breaking it open. That’s useful if you’d like to show off a sherd in amber, but you’ll need to mine it normally to get the Gloomsherd out.
Gloomslate Pots
To make a Gloomslate Pot, put four Gloomsherds in a plus shape on a 
Crafting Table, one above, one below and one on each side, with the middle and corners left empty. Each sherd becomes one side of the pot, so the order you place them in decides which pattern faces which way.
Gloomsherds won’t work on a vanilla 
Decorated Pot, and normal pottery sherds won’t go on a Gloomslate Pot either, so the two sets can’t be mixed. Unlike a Decorated Pot, there’s no plain Brick version, as every Gloomslate Pot needs four Gloomsherds of some kind.
Using a Pot
A Gloomslate Pot works the same way as a Decorated Pot, as you’re able to put a single stack of one item inside by using it on the pot, and it’ll wobble when you do. Using it with an empty hand just makes it wobble, and the pot will drop everything it’s holding when it breaks.
Breaking it with a tool like a Pickaxe or hitting it with an Arrow will shatter it back into its four sherds, which means you’re able to rearrange the patterns as many times as you like. Breaking it by hand, or with a Silk Touch tool, drops the pot in one piece instead.
FAQ
Mine fossilized Crystallized Amber in the Overcast Columns of the Otherside, which can hold a Brittle, Temple, Ward or Wayfinder Gloomsherd. The other five only drop from the Anger, Fear and Sorrow Pots, which don’t spawn naturally in 1.4.1.
Place four Gloomsherds in a plus shape on a Crafting Table, with the middle and the corners empty. Each Gloomsherd becomes one side of the pot, so you’re able to choose which pattern ends up on which side.
Gloomsherds only work on the Gloomslate Pot, and vanilla pottery sherds only work on the Decorated Pot. The two pots look and work alike, but their sherds can’t be swapped between them.
They were added in 1.4, which is only out for 1.21.1, so the 1.20.1 version of the mod doesn’t have Gloomsherds or the Gloomslate Pot. The Crystallized Amber on 1.20.1 still holds other loot, like Sculk Bones and Soul Dust.
