When “Mad Men” debuted in 2007, and I first noticed Joan Holloway wearing a pencil on a chain around her neck, I had an epiphany:
Lee Holloway, the central character in “Secretary” (2002), also wore a pencil on a chain around her neck, in a particularly memorable scene.
Joan Holloway was Lee Holloway’s mother! (That's my story, and I'm sticking to it.)
This kind of pencil necklace is often referred to as a "chatelaine", a term once used to describe "the woman of the house" who often wore a series of short chains around her waist, to which were attached things like keys, thimbles, scissors and other small, useful domestic objects.
And chatelaines often included pencils, typically enclosed in an ornate silver or gold holder. Chatelaines enjoyed a renaissance in the 1950s, in offices, libraries, and anywhere else someone might need a pencil in a pinch.
Here is a modern version:
And here are some antique and some whimsical examples (with a couple of them being more of an homage than being functional):
The best chance for a renaissance of the chatelaine pencil these days, given how most of us do work in an electronic way most of the time, would likely involve the Apple Pencil, or another stylus.