(STONE) [noun] [U] - a hard black stone which shines when rubbed and which is used to make jewellery and other decorative objectsHer parents gave her a pair of jet earrings for her birthday.If something is jet-black, it is very dark black.He has a dark complexion and jet-black hair.
JET
Meaning of JET in English
Cambridge English vocab. Кембриджский английский словарь. 2012