blue-black, a. and n.
A. adj. Black or dark with a tinge of blue.
| 1853 Q. Rev. Mar. 309 The coarse blue-black locks of the North American squaw. 1871 M. Collins Mrq. & Merch. II. i. 11 Face closely shaven, chin blue-black where the beard was..repressed. |
B. n. A pigment of this colour.
| 1823 P. Nicholson Pract. Build. 416 Blue-Black is the coal of some kind of wood burnt in a close heat. 1857 Ruskin Elem. Drawing 41 Take cakes of lake, of gamboge, of sepia, of blue-black, of cobalt. |
Hence blue-blackness.
| 1880 L. Wallace Ben-Hur ii. iv. 96 A bank of blue-blackness over in the west which they knew to be mountains. |