It must feel magical to a 7-year old!

He is keeping his card with him all the time.

I didn't check up on Applause, Inc. Given your research, I'm all the more skeptical about its authenticity. I will try to ask that acquintance how these cards came into his family. But like you, I also believe they got those from Ebay. There are plenty of sets still available there ranging from €2 to €14 for a single card. Stuff like this is very easy to sell especially when targetted at the right people.

I do have a basic microscope at home. I will see if I find something interesting. Thanks for the idea, I didn't think of it.

I didn't know one of my favourite childhood activity is a well-known experiment to find foreign particles.

There was a small dirt mound at the corner of my childhood home. I accidentally dropped my magnet in the dirt one day and was a little surprised to see some particles hanging with it. Since then, it became a fun activity for me and my siblings to collect those particles from the dirt. We used to think that we got precious rare metals and nobody knows about it. You know how kids especially pre-teens love to be secretive like they are part of something serious and adult stuff. 😅

Thankyou for sharing the experiment though. I had forgotten about it. I will do it again with my boys in the backyard since we don't have access to the rooftop.