Featured Chinese Carving with Signature

I would be EXTREMELY weary of doing the hot pin test.

If it's antique celluloid, you just turned it into a bomb. Old celluloid plastic is EXTREMELY flammable. It'll go off like a firecracker.

 

Please don't ever use the hot pin test on anything. As Shangas said, it could damage whatever you have.
Google is no authority on ivory, it is a search engine to look for sense and nonsense on the internet. More nonsense than sense.
Are you sure your item is by the same maker, do you have pictures of it?

 

I had an old, broken celluloid fountain pen from the 1930s.

To find out what all the hype was about celluloid and its legendary flammability, I set the pen on fire.

The damn thing fizzed, popped, smoked, went off like a damn firework and then burst into flames.

I did this in my fireplace, just to be safe, but the results were alarming, let's just say that much.

If you do the hot-pin test on something, and it's antique celluloid, I don't think you want that happening in your bedroom at your computer, while you're holding the pin in one hand, and have the item in front of your keyboard on top of your desk.

Guitar-picks are one of the few things still made of celluloid today - the same material they used for fountain pens back in the 20s and 30s.

This is what happens when you expose it to extreme heat, or open flame:



I don't think you want this happening on your desk.