Case Hardened skins are tinted by a paint seed, one of 1000 patterns. The seed fixes the blue, gold and purple layout on the weapon, so two Case Hardened of the same wear can look completely different and trade at very different prices.
Seeds with heavy blue coverage on the most visible side are called "Blue Gems". On the AK-47 the best-known examples are seeds like 661, 670 and 955; on the Karambit, seed 387 is the reference Blue Gem. Tier lists rank seeds by blue percentage, and top patterns command large premiums over an average Case Hardened.
Because the seed is not shown in the item name, buyers check the paint seed in the inspect screen or a pattern database before paying a Blue Gem price.
Across 23 markets the WW floor moved -71.7% in 185 days: $77.56 → $21.93.
Cheapest venue vs Steam right now: $9.69 apart (31%).
Sources: Valve item data · our 23-market price snapshot.
How much does MAC-10 (Case Hardened) cost?
MAC-10 (Case Hardened) starts at $20.12 across 23 marketplaces in our comparison, buyer fees included. Current floors by wear: FN $40.62 · MW $24.50 · FT $22.83 · WW $21.93 · BS $21.77. Steam asks $31.62 for the same listing.
Where can I sell or cash out MAC-10 (Case Hardened)?
Top net quote at the moment: $21.46 via CSFloat, seller fee already deducted (see the Sell tab for every venue). Steam credits $79.84 to your wallet, and wallet money cannot be withdrawn.
Does MAC-10 (Case Hardened) come in StatTrak or Souvenir?
It does — Souvenir (from $20.12) listings exist too. Pick a Quality pill above to see that variant priced across the same markets.
How do I get MAC-10 (Case Hardened)?
The drop source is Stockholm 2021 Dust II Souvenir Package, itself listed from $3.27; the direct market price starts at $20.12. Opening containers for one specific skin rarely beats buying it outright.
Stockholm 2021 Dust II Souvenir Package
Inspect a WW copy in game 
