Known as 點翠 / 点翠 to the Chinese, Tian-Tsui translates to "dotting with kingfishers". Its a traditional practice in which tiny kingfisher feathers were cut to size and incorporated into sterling silver and silver gilt jewelry to create a dazzling fluorescent blue finish.
This type of jewelry was made for over 2000 years in China. The techniques were largely lost with the Chinese cultural revolution in the 1940s. These tiaras are antiques which were made by hand in the first half of the 20th century.
"Surprise me" variant may will be a tiara of similar size and condition to those pictured.