CS2 Pattern IDs and Blue Gems, Explained
2026-09-25 · 4 min read · CS2
Two copies of the same CS2 skin can look completely different. That's because many skins use a pattern seed, a number from 0 to 1000 that decides how the texture is placed on the weapon.
How patterns work
When a skin drops, it gets a random pattern seed. For most skins the difference is small. For a few, it changes everything.
Case Hardened and "blue gems"
Case Hardened skins mix blue, gold and purple. Some seeds put almost solid blue on the most visible side of the weapon. Collectors call these blue gems, and the best seeds sell for many times the price of a normal copy. The AK-47 Case Hardened pattern 661 is one of the most famous examples.
Other pattern-driven skins
- Fade skins are valued by how much of the gradient shows. - Doppler knives come in phases, plus rare Ruby, Sapphire and Black Pearl variants. - Marble Fade and similar finishes have named patterns like "Fire and Ice". - Some newer skins and charms have rare color variants too.
Checking a pattern
Inspect the skin in-game or use a float and pattern checker, which shows the seed and float value. Pattern guides and sales history tell you whether a seed is special.
A word of caution
Rare patterns are a collector market. Prices depend on a small number of buyers, so they can be slow to sell.
See where to trade rare skins in our skin trading rankings.
