Uncountable noun referring to the colour itself.
The accent wall was painted in a deep brick-red.
Le mur d'accent était peint d'un profond rouge brique.
Colour adjective, usually attributive, describing a hue similar to that of red bricks.
She wore a brick-red sweater that matched her lipstick.
Elle portait un pull rouge brique qui allait avec son rouge à lèvres.