Not 100% sure this is a mustard pot as it quite large, perhaps salt cellar, or some sort of cranberry type sauce . approx 8 inches tall lovely dolphin finial good for a resident Brighton England, a coastal town whose emblem includes a stylized dolphin of I think 18th century design origin. the age of this pot is on the surface quite old. Internet and book research suggests its of French design. a great piece. ships worldwide for free.