Lustrous black that runs deep toward the skin. The under color (next to the skin) should be slate blue in color.

The eyes should be brown

Nails should be dark.

Faded or Rusty tinge to coat, Scattered White Hairs, Uneven color.

White or off colored spots, White or mismatched nails, any other eye color than specified. 

Self Black, Solid Black

aaB_C_D_E_
aaB_C_D_Es_
aaB_c(chd)_E_
aaB_c(chl)_E_

Stray white or gold hairs may indicate the Black is hiding the Steel gene or is an Agouti based super steel, A_B_C_D_EsEs rather than a self based Black.