Rarity is a measure of how 'advanced' an item is. Rarity is detemined by taking the sum of an item's components. For example: Dirt (Rarity 1) and Cave Background (Rarity: 1) can be spliced to make a Door (Rarity: 1+1=2). As an item requires more steps to splice, it will typically gain a higher rarity.
Some special items like Dragon Hand don't have a rarity, so they are considered to have a rarity of 999.
Chemical Combiners also work to increase the Rarity, combining 10 Chemical G (Rarity: 1), 5 Chemical B (Rarity: 25), and 5 Chemical Y (Rarity: 15), you get a Steel Table (Rarity: 1 + 25 + 15 = 41), {Note that the rarity does not stack}.
Recipes involving the Transmog Crystal have rarities based on the rarity of the base material. For example, a Blue Sun Shirt is made by combining a Happy Sun Shirt (Rarity: 42), a Transmog Crystal (Rarity: 87) and 20 Blue Block (Rarity: 15). Because the rarity of the base material is 42, the rarity of the product is 42 as well.
Few other select recipes have "defiant" rarities.
Rarity directly controls:
- Gem drop rate (from blocks, as well trees); roughly one gem every additional 4 rarity.
- Tree growing time
Rarity has no effect on block drop rates from trees, or seed drop rates from blocks.
Note: not to be confused with recipe tiers.