Rare Vintage Solid 10 Carat Gold & Enamel Comptometer Maths Ring.

Rare Vintage Solid 10 Carat Gold & Enamel Comptometer Maths Ring.
Originally made by United States jewelery Ostby & Barton who ceased operations in 1950.
The ring has enameled detail with mathematical symbols. Above is the word comptometer.
These rings were awarded to students who performed exceptionally well whilst learning the comptometer and it dates to the first half of the 20th Century.
Stamped 10k as pictured & with its original box
These rings now appear very scarce with very few coming through the markets.
Size: internal diameter is 15mm.
Weight: 2.8 grams.
See all 17 images.