I found the large (just under 2 inches in diameter!) magnifying lens while poking around the medical section of a university book store. I believe it was intended for use in examining wounds and such.

I set the lens into a fine silver bezel and a sterling silver bail. The beaded chain is nice and long, adjustable from 23 to 25 inches and finished with a custom sterling clasp. Beads are small faceted rondelles, including Labradorite, moonstone, and apatite.

Quizzing: 'The act of mocking by a narrow examination through a quizzing-glass or by pretended seriousness of discourse'. -Royal Dictionary Cyclopedia of Universal Reference by Thomas Wright, 1865