We got our hands on some old Soviet-era glass composite sheets. These are from the 1970s at the latest, and show a very interesting patina. Under the surface, you will find three off-white stripes, which over time will become brown. To speed up the process, after shaping, you can put your scales in direct sunlight for a day, or a UV lamp for a few hours, and that will be enough to turn those layers brown. The example in the photos is what it looks like after 2 hours under UV, though it looks the same after a day in the sun. Keep that in mind for the final product.
 
Approximate Size: 5 x 1.55 x 0.365 inch scales.
The listing is for a pair of scales.