Andrew Nethercott Antiques has dated this piece to the 1880s.

The base of the egg is marked Rd No 20772 a design registered to James Macintyre's Washington China Works, Burslem.
Length 2,3/8" or 62.5mm weight 25 grams
The egg in excellent condition with no damage or repair, the silver lid with dents to the dome, no holes or splits, good thread work.
Andrew Nethercott Antiques has dated this piece to the 1880s.
Works of art, collectables, scientific and decorative antiques from the 17th - 20th century
You can view the stock and full dealer information on the Andrew Nethercott Antiques Profile Page