In heraldry, gules (/ˈɡjuːlz/) is the tincture with the colour red, and belongs to the class of dark tinctures called "colours". In engraving, it is sometimes depicted as a region of vertical lines or else marked with gu. as an abbreviation. In Polish heraldry, gules is the most common tincture of the field. Through the sixteenth century, nearly half of all noble coats of arms in Poland had a field gules with one or more argent charges on them. The original coat of arms of the d'Albret family was plain gules. * of jewels, the ruby; * of heavenly bodies, Mars.