It's not a glass medallion, if that's what you're referring to. It's painted a gloss black, probably some kind of urethane material. Could be this one, check the customer photos in the reviews. Someone painted it with a high gloss black and it looks like your inspiration pic

https://www.wayfair.com/home-improvement/pdp/ekena-millwork-24-34od-x-3-14id-x-1-78p-eryn-ceiling-medallion-fits-canopies-up-to-4-ekml2749.html?piid=

Yeah, that’ll look good on the popcorn of a 96” 1979 ranch house. Because it looks so good and not at all pretentious ”adding interest” in that McDesigned train wreck tray ceiling.

Tozmo1 is correct, it can be found on Wayfair. Here is a pic from a reviewer that spray painted theirs in gloss black.

Tozmo is correct. (ETA: And Amy Lynn. We were posting at same time.)

It belongs to this blogger; she used Rustoleum black spray paint, you can see in her dining room stories:

https://www.instagram.com/p/CI9B6_nnjUs/?utm_medium=copy_link

https://www.instagram.com/p/CEF4MzMJWdC/?utm_medium=copy_link

https://www.instagram.com/p/CB_I4NYlgXS/?utm_medium=copy_link

She said the color in the photo is because it’s reflecting nearby green walls.

Lots of places sell this medallion, do a search for more.