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Counter-Strike 2 > Guides > korenevskiy's Guides
250 ratings
The Complete Blue Gem Patterns Guide
By korenevskiy and 1 collaborators
The ultimate guide to all Blue Gem patterns for all knives. In this guide I will show you all rare patterns on Case Hardened.
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Created by
Krieke 啤酒哥
Offline
korenevskiy
Offline
Languages: English
Equipment: Knives, Pistols, Rifles, SMGs
Posted
Updated
Nov 20, 2023 @ 11:29am
Nov 9, 2025 @ 2:56am
74,606 Unique Visitors
514 Current Favorites
Guide Index
Overview
Blue Gem 
Heat Treated 
Case Hardened 
⠀ 
⠀ 
⠀ 
Gold Gem Guide 
Comments
Blue Gem
Blue Gem is the name for Case Hardened skins with the maximum amount of blue on them.

In CS2 there are 20 different knives, AK-47, Five-SeveN and MAC-10 with Case Hardened pattern. All of them are very popular, although each weapon has its own hits.

Some skins in CS2 won’t look differently with various Pattern Indexes. But with Case Hardened, it’s the opposite. Patterns decide everything and the price can jump ten times depending on the number. The most expensive skins in this series are almost entirely blue, they’re called Blue Gems.

These skins are considered very rare and super valuable among traders and players. The most famous Blue Gem skin is AK-47 Case Hardened with Pattern Index #661.



There are four different tiers in the index, numbered 1-4 in order of value, with 1 being the highest and 4 lowest.

Tier 1 patterns have the highest amount of the Blue stain from the Case Hardened finish, and thus generate the highest amounts of overpay for the skin, sometimes several times over the average market value, due to their rarity and demand. The amount of the blue stain gradually decreases as you go down the tiers, and the least amount is present on patterns from Tier 4, which are equivalent in value to the average market value at which the skin sells for.

Case hardened skins have lots of unique patterns. Certain patterns with more of the light blue color are valued higher by the community. These skins are referred to as "Blue Gems". The patterns are completely random for every seed so there is no easy way to sort them to find the ones with the most blue.

Texture Masking
In the Case Hardened texture, you can see the light blue areas on the left, and top left. There are also a few smaller areas scattered around the texture.

In order to get an accurate representation of the amount of blue applied to a specific weapon model, a color mask is applied over the top of the blue areas. We can then detect that specific color mask when reading the model and calculate the percent of blue visible on the model.



It’s a square texture that is applied to the weapon model randomly. The texture’s location is determined by a number from 1 to 1000. These numbers are called Pattern Index.
27 Comments
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ツ︎☯︎14AlOnE37♫ Jan 3 @ 3:22am 
exchange a tempered body kukri (fn) 549 with a blue heart for the only fn in the database
макан Nov 29, 2025 @ 12:25am 
★ StatTrak™ Kukri Knife
Blue Gem
World's First FN
Pattern 371
Float 0.035024166
Over 80% Blue
Waiting for the best offer
https://steamcommunity.com/tradeoffer/new/?partner=348375142&token=ZWKjZuxm
yaqqqazerisss Oct 31, 2025 @ 10:30am 
How much does a desert eagle cost? tier 2
TWOBIGNUTTZ Oct 21, 2025 @ 3:03pm 
https://steamcommunity.com/tradeoffer/new/?partner=1855366756&token=66nQQXmH

tier 1 blue gem falchion for trade would love a classic knife
Chuality- Oct 19, 2025 @ 11:21am 
https://steamcommunity.com/tradeoffer/new/?partner=278559840&token=ZHw2oVHk

TIER 1 Blue gem. Pattern - 674
Trading Desert Eagle Heat Treated WW
ßαlςα Oct 10, 2025 @ 1:15pm 
trade shadow daggers tier 2 blue gem st mw (patter 883)
Grāpis29 Sep 30, 2025 @ 12:10am 
Looking to trade T3 Ursus bluegem 916
Bellair08 Jul 29, 2025 @ 2:34pm 
hello sir i have a request for the best pattern on a pattern based skin not listed here or anywhere else that I could find. Would you be able to help me find the best pattern im looking for or someone that could help me?
俄罗斯 Jul 20, 2025 @ 7:59pm 
how much will a butterfly knife cost case hardened 182
BossAndrew Jul 18, 2025 @ 9:44am 
Desert Eagle | Heat Treated Rank 1 Blue Gem https://steamcommunity.com/tradeoffer/new/?partner=450956978&token=OIagOPNQ