Yay!!! Did you mark her yourself? If so, what do you use?
Yes, I marked her myself.
I had her in a clip type queen holder, so took her in the bathroom in case she flew, I put my finger at the edge of the clip so she would walk on it.
Let her hold your index finger with her legs, she will readily do this
Then while holding her, dab a spot of the appropriate color on her Thorax.......hard round spot behind her head.
Must be very careful not to get on her wings or body other than Thorax.......both can damage her.
Be sure to be ready.........you have already dubbed your paint stick a few times and wiped it off, prepare a small drop on the end of paint stick, so you can just do it and put her back in clip or container to dry.
Now I wish I could find my other 2 Queens and get them marked but those both have 2 deep boxes and boiling with bees, will be hard to find.