The Sentinels use a black base with gold accents as their color scheme.
Per Field Manual: 3085, p.180
Other Reference: none
The Sentinels’ insignia is a black stylized Ionic column capital inside a gold diamond. As with the other line brigades, the Hastati indicate their home Prefecture with a superscripted Arabic numeral to the right of their brigade insignia and their particular regiment designation with a subscripted numeral to the left. Per Field Manual: 3085, p.180