Bismuth

Bismuth is a very rare ore which comes from the deepest heart of the nether, with it having a 10% chance to drop per ancient debris with it dropping after 10 ancient debris. It however doesn't drop in its Bismuth form, coming in as shards used to forge the Bismuth crystal. It was first added in v1.07 along with bismuth shards, armor and bismuth grappling hook. You can see the full bismuth texture to the left of this explanation.

Crafting Bismuth
Bismuth can be crafted into its crystal form by entering a crafting table and combining it with 4 netherite ingots and 4 bismuth shards - similar to the standard netherite ingot recipe with the netherite replacing the scraps and the bismuth shards replacing the gold in the recipe. You can find an image of its crafting recipe to the left of this explanation.

Bismuth In Crafting
Bismuth crystals primary use is for crafting armour and specialized tools - with the armour being bismuth armour and the specialized tools being bismuth grapple hooks and Major tiered witch charms. The armour recipe is similar to the default armour recipes with each piece being in its stereotypical slot, with bismuth chestplate needing 8 bismuth and bismuth leggings needing 7 bismuth - and the bismuth grappling hook requiring one bismuth, 2 netherite ingots, and 2 chains.

Bismuth Armour
Bismuth Armour is a set of Armour made of Bismuth Crystals - it is statistically worst then netherite by one in stats, however doning a full suit of Bismuth grants the wearer buffed racial abilities such as Skeletons going fasters on a landed arrows. You can find the racial buffs on the races page in a section all about their stats when wearing bismuth armour.