These charming antique ironstone 'diabolo' style egg cups, named after the child's toy, have become very collectible and especially so in the Marie Louise teal floral design by St Amand, which is highly sought after. It dates from the 1890s.
 
They can be used either way up, which is good as one has a tiny rim nibble, which is indicated by the arrow. They stand 2.5" tall and 2" in diameter.