Folding Fan has a diamond pattern formed by arcs on the inside of these smallish compotes. Usually seen in peach opal, I know of only seven sales of purple examples: one for $170 in 1993, this beauty, owned by Carl and Eunice Booker, and one by Larry Keig. A fourth sold at auction in 2005 for $170 and another in 2008 for $525. One sold in 2011 for $390. Another example, perhaps one of the previous, sold in 2021 for $1,100. Don't confuse with a similar Westmoreland pattern, File and Fan.
Hartung Book Six: Folding Fan
Compotes
Updated 12/3/2022
Marigold on milk glass, 50 (2020)
Marigold on moonstone, 70 (2015)
Blue opal, 65 (2018), 80 (2020)
Peach opal, 10, 15 (both 2020), 15, 20 (both 2022)
Peach opal, 2 sides up, 15 (2017), 10, 20 (both 2019)
Purple, first reported, 350 (2021)