Codex Unforgiven

Color scheme

The chapter's main colors are dark green with silver-colored greaves and trims around the shoulder pads. Brother-marines wear a green helmet whereas veterans paint their helmet silver upon induction into the Deathwing. These veterans can also opt to wear bone white colored robes, but not all of them do this, either for personal dislike or practical reasons, like assault marine veterans for example.

Marine 

Veteran (Deathwing)