The Caithness thimbles I have were in a collection of thimbles of all kinds that my aunt owned. Seven years ago, she became bored with her thimble collection and gave it away bit-by-bit to relatives and friends. An uncle, for example, got the ones that had names of and designs from national U.S. parks on them because he collects national park memorabilia. The collection contained around 250 pieces. I got two, the Caithness glass thimbles, the only two glass ones she had. She noted that they were purchased together, new by her, in the 1980s; she thinks the mid-80s, at a store called Birk's in Toronto.
By the way, at 72, my aunt is still collecting many other things. She has some incredible Rookwood pottery and an original Tiffany (LCT) lamp plus a lot of nifty Pan-American Expos and World's Fairs items. She also has two pieces of classic antique Lalique and some items that contain the name of the Paris arts and decor expo that gave us the name "Art Deco." Her newest passion is collecting tiny hand-made folk art thingies, like little figures or animals or farm buildings. She is truly an incredible lady.