I'm a totally sucker for zircon. The doubly refractive nature of the stone means that they are super sparkly, and these earrings are articulated, which only adds to that. 
Zircon was really popular in 1930s and 40s jewellery, which is the time these earrings were made. 
Crafted in yellow and white gold, and set with rose cut diamonds to the tops, these have hookwire fittings making them super easy to pop in and wear. 
Tested as 18ct gold 
Weight approx 2.25g
Total drop approx 24mm 
Width approx 7mm
Excellent antique condition