Featured Windsor glasses - tortoiseshell frames?

I picked up these great old sunglasses today for the princely sum of $12 Canadian. In the shop I could hardly see through the lenses but, happily, a wash with soap and water revealed them to be in near-perfect condition. I understand that Windsor-style glasses like these were fashionable from the 1880’s through the first quarter of the 20th century, and these “feel” quite old to me, but I’m not sure when they date to. I also can’t decide if the frames are plastic (in which case the glasses can’t be any earlier than the 1930’s) or real tortoiseshell (which could mean they’re older). What do you think?

 

I'd say plastic....

 

To distinguish colored plastic from real tortoiseshell, examine it with a good magnifying glass or jeweler's loupe. The dark areas in tortoiseshell will appear as dots of pigment. If plastic, the colored areas will look more like a smooth wash.

 

Thank you! I will do this.

 

Those are very cool! Do you plan to wear them? I would if they fit ok.

 

I just might wear them!

 

Okay, had a close look and am seeing dots. Also, the frames show signs of being carved, rather than injection molded. So, tortoiseshell? I understand that, if not real tortoiseshell, frames for Windsor glasses like this could be made of celluloid, or casein plastic. I’m not familiar enough with these early plastics to recognize them, though.

 

If the lenses are glass they probably are not safe to wear.

 

Because of the risk of shattering?

 

Yes, if they were made before 1970 and have no/minus prescription the center is probably below 2mm thick and not heat treated.

 

Okay, thank you!

 

https://www.researchgate.net/public...rization_of_Tortoise_Shell_and_its_Imitations

 

While looking for pigment dots with a loupe, I accidentally discovered a tiny little impressed mark that I hadn’t noticed before:



Turns out, it’s the logo of the American Optical Company used from 1889-1911!