Doppler phases, fade % and blue gems, explained
Two copies of the same CS2 skin can be worth wildly different amounts. Here’s what decides it — Doppler phase, fade percentage, Case Hardened pattern and paint seed — and how to check yours.
Updated 2026-09-14 · Patterns & rarity · Free tool included
Quick answer
A skin’s pattern attributes — set at drop by a random paint seed — can matter more than its name. Doppler phase (Phase 1–4, plus rare Ruby, Sapphire, Black Pearl or Emerald), fade % (how much of the colour gradient shows), and Case Hardened blue-gem patterns each swing the price hugely. None of them show in your Steam inventory by default — you read them from the inspect link, or let a tracker detect them.
When a skin drops, Valve rolls a hidden paint seed (0–1000) and a float (wear). Those two numbers decide the exact look — and for certain finishes they turn an ordinary skin into something collectors pay multiples for. These are the patterns that move the price.
Doppler phases
Doppler (and its Gamma, Sapphire-toned and Ruby-toned variants) isn’t one skin — every one is a specific phase, and the phase sets the colours and the price. Phases 1–4 are the common numbered outcomes; Ruby, Sapphire, Black Pearl (and Emerald on Gamma Dopplers) are the rare, far pricier tiers.
| Phase | Look | Value tier |
|---|---|---|
| Phase 1 | Black with blue/violet, hints of pink | Mid |
| Phase 2 | Strong pink with blue — the “pink” phase | High |
| Phase 3 | Blue-dominant with pink accents | Mid |
| Phase 4 | Mostly deep blue/black, clean look | High |
| Ruby | Full deep red | Top — rare |
| Sapphire | Full bright blue | Top — usually priciest |
| Black Pearl | Black with a single swirl of colour | Top — rare |
| Emerald (Gamma only) | Full green | Top — rare |
Phase preference is partly taste — Phase 2 (pink) and Phase 4 (clean blue) are the most sought numbered phases, but the rare tiers outvalue all of them, with Sapphire usually the priciest.
Fade percentage
Fade skins carry a colour gradient, and the fade percentage is how much of that full gradient landed on the skin — driven by the paint seed. On most Fades a higher % is more desirable, with 90%+ and especially a 100% “full fade” commanding a clear premium over a plain one. A handful of skins are judged on the exact colour balance rather than raw %, but higher is the safe rule.
Case Hardened blue gems & paint seed
On a Case Hardened (and Heat Treated) skin, the paint seed decides how much blue lands on the visible side. Seeds with heavy blue coverage are “blue gems,” and the best-known patterns — like the legendary AK-47 pattern 661 — sell for enormous multiples of a normal copy. The same seed logic drives Marble Fade “Fire & Ice,” Crimson Web placement, and more: two identical-named skins with different seeds can be worth wildly different amounts.
How to check yours
None of these show in the Steam inventory — the phase, fade % and seed live in the item’s inspect link. You can paste that into a third-party inspector, or let a tracker read it for you. SkinROI detects Doppler / Gamma Doppler phase, computed fade %, paint seed, and Case Hardened / Heat Treated blue-gem tier and rank automatically when it values your inventory — so a special pattern is priced as the pattern, not as a generic copy.
See also: how to check your inventory value · live prices across all four markets
Value your patterns properly — free
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Frequently asked questions
What is the best Doppler phase?
Among the numbered phases, Phase 2 (heavy pink) and Phase 4 (clean deep blue) are usually the most wanted and priciest, with Phase 1 and Phase 3 a step below — though it comes down to taste. The rare tiers sit above all of them: Ruby, Sapphire and Black Pearl on a normal Doppler, and Emerald on a Gamma Doppler. Sapphire is typically the single most expensive.
How do I check my Doppler phase?
The phase isn’t shown in the Steam inventory by default — you check it from the item’s inspect link with a third-party inspector, or use a tracker that reads it for you. SkinROI detects the Doppler / Gamma Doppler phase (Phase 1–4, Ruby, Sapphire, Black Pearl, Emerald) automatically when it reads your inventory.
What’s the difference between Ruby, Sapphire and Black Pearl?
They’re the rare “special” Doppler outcomes instead of a numbered phase. Ruby is fully red, Sapphire is fully blue, and Black Pearl is black with one swirl of colour. All three are far rarer and more expensive than Phases 1–4; Sapphire is usually the most valuable. On Gamma Dopplers the equivalent rare tier is Emerald (fully green).
Is a higher fade percentage better?
On most Fade skins, yes — a higher fade % means more of the full colour gradient is on the skin, and 90%+ (especially a 100% “full fade”) sells for a premium over a plain Fade. A few skins are judged on the exact colour balance rather than raw %, but as a rule higher is worth more.
How do I check a skin’s fade percentage?
Fade % is computed from the skin’s paint seed, so it isn’t in your Steam inventory directly — you read it from the inspect link with a fade calculator, or let a tracker compute it. SkinROI shows the computed fade % for Fade skins automatically.
What is a Case Hardened blue gem?
A “blue gem” is a Case Hardened skin whose paint seed happens to place a large amount of blue on the visible side. The pattern index (paint seed) decides it, and the best-known patterns — like the legendary AK-47 pattern 661 — sell for enormous multiples of a normal Case Hardened. Heat Treated finishes work the same way.
What is paint seed (pattern index)?
Paint seed is a value from 0–1000 that Valve rolls when the skin is created; it decides how the pattern is placed. It’s what makes Case Hardened blue gems, high-fade Fades, Marble Fade “Fire & Ice,” and Crimson Web placements rarer and pricier — two copies of the same skin with different seeds can be worth very different amounts.
Why are two of the same skin priced so differently?
Because the item name is only part of the story. Float (wear), Doppler phase, fade %, Case Hardened pattern, StatTrak and applied stickers all change the price. A valuation that only reads the name misses most of what collectors actually pay for.
What is a Gamma Doppler Emerald?
Emerald is the rare special phase of the Gamma Doppler finish — a fully green blade instead of a numbered phase. It’s the Gamma Doppler equivalent of Ruby/Sapphire and is one of the most valuable knife finishes in the game.