Briarberry- You may be thinking of what is called a "bone folder" for setting creases in paper. I agree this is very wide for a letter opener- maybe for opening packages? Thank you everyone for the pictures. Mine is in a trunk- not accessible at present. Wonder if it's bone or celluloid?

I think it is a letter opener too but I would have used it to push out the corners that I sewed-----

I have one too, except mine is a light green. I think mine is plastic. I never knew what it was for, either.

It's a bone folder for creasing paper regardless of whether it is made of bone, ivory or plastic.

These were sent out by some of the "Missions" during the 40's & 50's. I have several, one is still in the original envelope from Indian Missions, Kansas City, KS. They are plastic, and they are letter openers. They asked for $1.00 donation to keep the letter opener or please return in enclosed envelope.

Do you suppose it's an early version of the tool we use to " finger press"?

What is it?
 

Ok, I will put my two cents in... I think it is a hand iron. You rub it across something you want pressed. what do you think? maybe?

its celluloid. thanks everyone. the mystery is solved. just another reason why I love it here. love you gals a bunch!!!!

Ditto to the letter opener. Mine was in grandma's treadle to. Guess it kept it safe from grandpa losing it!

Its either a letter opener or thread cutter!