Dates to the early Art Deco era, circa 1920.
Crafted in solid 14K yellow gold, and hallmarked as such on the pin stem. Also bears a partial maker's mark, but as it is only partial, I am unable to identify it.
Fabulous geometric design, featuring a truly unique gemstone. The square step-cut stone measures approximately 4.3 mm from edge to edge, and 5.5 mm from corner to corner (top to bottom). If you look at the deep red stone with a loupe and a light, you can see the rutilated lines running through the stone, which look like tiny needles. (This did come from the collection of a rare gem enthusiast, which accounts for the use of such an uncommon stone.) Finished at the base with a post-set genuine seed pearl.
The stickpin measures 2.69" from end to end, with a top portion that measures 0.86" by 0.43". This piece weighs a solid 1.9 grams.
Condition is very good, with no repairs. I did note two very tiny nicks to the facets on the backside of the stone, but I am thinking that these are actually natural inclusions due to the nature of the stone.