Butterfly, Westmoreland
While these are marked with the Westmoreland logo, they were not made by Westmoreland, but by one of the contemporary makers. They have about a 4-inch wingspan. I know of them in this blue and a sort of mother-of-pearl. They sell on eBay for $12 to $18.

In 2022 a peach colored example sold for $35 and one in purple brought $35.

Updated 2/28/2022