The AK-47 | Case Hardened is one of Counter-Strike's most famous finishes — not because of its base art, but because of the extreme pattern-index variance built into every Case Hardened finish. Each Case Hardened has a randomised pattern seed (0–999) that determines the ratio of blue, purple and gold surface. Those with rare mostly-blue faces are called Blue Gems, and command 10x–100x the price of a regular Case Hardened.
The Blue Gem community has been mapping seeds for over a decade. Reference sites like csbluegem.com maintain seed-tier lists — Tier 1 (perfect Blue Gem, near-uniform blue playside), Tier 2, Tier 3 and "scammer tier" (partial blue that some sellers try to pass off). Widely-known Tier 1 seeds like 661, 670, 321 and 555 sell for five-figure sums even in Battle-Scarred wear.
This page hubs together the Case Hardened variants active in our database. Because the skin's value is pattern-dependent, prices here reflect the average Case Hardened in each wear — a true Blue Gem always requires manual pattern inspection through the Steam inspect link and a cross-check against a reputable pattern index.
All variants — live prices
Frequently Asked Questions
What is a Blue Gem in CS2?
A Blue Gem is a specific AK-47 Case Hardened whose randomised pattern-index (seed) produces a near-uniform blue surface, especially on the playside (the visible face when the weapon is held). Blue Gems are the rarest tier of Case Hardened patterns and can sell for 10–100x the price of an average Case Hardened in the same wear.
How do I check if my Case Hardened is a Blue Gem?
Open the Steam inspect link (in-game right-click → Inspect), then compare the pattern index against a public reference like csbluegem.com or the r/GlobalOffensiveTrade Blue Gem seed list. Focus on the playside coverage — a true Tier 1 Blue Gem has near-complete blue on the barrel, receiver and stock viewed from the visible side. You can also use our free /tools/float-checker/ to decode the inspect URL.
What are the top Blue Gem seeds?
The widely-recognised Tier 1 AK-47 Case Hardened seeds include 661, 670, 321, 555, 179 and 151, among others. Each has slightly different playside coverage; 661 is generally considered the "king" seed. Full seed rankings are maintained by the trader community — pattern coverage varies within a seed based on wear and stat-track.
How much does an AK-47 Blue Gem cost?
A confirmed Tier 1 AK-47 Case Hardened Blue Gem in Factory New has sold for $150,000–$400,000; Field-Tested Tier 1 typically clears $30,000–$80,000; even Battle-Scarred Tier 1s trade in the $10,000–$25,000 range. Lower tiers (Tier 2/3) are worth 30–60% of Tier 1 comps in the same wear.
Are Blue Gems only on the AK-47?
No — Blue Gem pattern grading applies to any Case Hardened finish: the AK-47, USP-S, Five-SeveN, MAC-10, and knives (Karambit, M9 Bayonet, Butterfly and others). Knife Blue Gems, especially Karambit Case Hardened Tier 1, are the most expensive category by far.