How Case Hardened patterns work
When a Case Hardened skin drops, Valve assigns a pattern index between 0 and 1000. That index is permanent — it doesn't change across trades, doesn't degrade with use, doesn't depend on float. Internally the pattern index seeds a pseudo-random generator that decides where each blue / gold / silver patch sits on the model.
Two skins can have identical pattern indices on different weapons — but the visual outcome differs because each weapon model maps the pattern onto a different UV layout. So pattern 661 on a Karambit gives a different "Blue Gem" view than pattern 661 on an AK-47. Each weapon has its own Blue Gem tier list.
The famous AK-47 Blue Gems
For the AK-47 Case Hardened, the community has settled on a widely-accepted tier list:
| Pattern | Tier | Why it matters |
|---|---|---|
| 661 | Tier 1 | ~95% blue receiver; the canonical Blue Gem. Past sales have hit $1M+. |
| 670 | Tier 1 | ~90% blue, second-most-famous; consistently $200K+ in StatTrak FN. |
| 955 | Tier 1 | ~88% blue, slightly more gold than 670; ~$150K+ in lower wears. |
| 387 | Tier 2 | ~80% blue, regularly trades at $30K-80K depending on wear. |
| 179, 219, 555 | Tier 2 | 70-80% blue, $10K-40K range. |
| 868, 168, 168 | Tier 3 | 60-70% blue, $3K-15K range. |
Knife Blue Gems
For knives, Karambit / Butterfly Blue Gems are the most expensive because the playside (the side you see in your hand) is large and visible. Pattern 387 on a Karambit, for instance, has cleared $400K in private sales. Bayonet, M9 Bayonet, Talon and Stiletto also have well-known Tier 1 patterns — each knife has its own community-maintained list.
Many knife patterns favour the "B-side" (the underside you don't see when wielding), which the community calls "B-side gems." These trade at 30-60% of the equivalent playside-blue price.
How to verify a Blue Gem claim
- Check the pattern index. Marketplace listings show it directly under the float panel. If it's not listed, use the in-game inspect (type
inspectin console after the inspect URL). - Cross-reference the community tier list. Csgostash, the Case Hardened subreddit, or the Blue Gem Discord maintain canonical lists per weapon. A "Tier 1 661 AK" claim is verifiable in 30 seconds.
- Inspect the playside in-game. Pattern indices can be misleading on weapons with a known "Tier 1 but bad render" exception. Always run inspect before paying premium.
- Compare to recent sale history. Large marketplace auction histories and Steam Community Market sales show real-world clears for the specific pattern. A seller asking $200K for pattern 661 when recent sales cleared $150K is overpricing.
StatTrak and wear interactions
StatTrak adds 30-80% to Blue Gem prices — collectors hunt clean StatTrak versions because the kill counter accumulates value over time. Lower wear (Factory New, then Minimal Wear) preserves the blue surface crispness; high-float Blue Gems still command big premiums but with a noticeable "weathered" look that some collectors actually prefer.
The only float range that hurts Blue Gem value substantially is Battle-Scarred (0.45+). Past that the rust-scratch effects can bury the pattern visibility.
Browse Case Hardened skins
Our catalog tracks every Case Hardened skin with current live pricing. Common entry points: AK-47 | Case Hardened, Karambit | Case Hardened, M9 Bayonet | Case Hardened.
Pattern index isn't tracked in our catalog yet for every drop — we display it when authoritative data is available. For now, treat our pricing as the "floor" (worst pattern) for that weapon and verify pattern grade via the marketplace listing before paying any Blue Gem premium.