Vintage Green Onyx Waltham 8-day clock

Vintage Waltham 8 Day Desk Clock, likely from the Art Deco era of the early 20th century (1911-1940).
Here's what we can learn about this type of clock:
Manufacturer and Type: It is a mechanical, 8-day desk clock manufactured by the Waltham Watch Company, as indicated by "WALTHAM" and "8 DAYS" on the dial.
Case Material and Style: The clock features a prominent green onyx base and case, characteristic of the Art Deco style popular during its likely period of manufacture.
Movement: This type of clock typically houses a mechanical movement designed to run for eight days on a single winding, often identified by a specific grade and jewel count (e.g., Grade No. 809B, 37s, 9 jewels as seen in a similar example).
Historical Context and Use: While the specific clock in the image appears to be a desk clock, Waltham 8-day movements were also famously adapted for use as automobile dashboard clocks or travel clocks due to their robust nature and long power reserve.