Nice to find Siam jewelry in white - so often, the colors are dark, and the Siam dancer design can’t easily be seen. These are delightful - the dancers stand out well on these screwback earrings. They were probably made in the 1930s-40s, and are clearly marked as sterling.
Size is a generous one inch high, and the style is quarter-moon in shape. They are in Very Good Condition, with the screws working well.