Howdy and Welcome.
Don't know if you know about Gnome color chooser
yet. It will be in Mints package manager.
I tried emerald, but it locked up the system. (borders and bottons disappeared and computer locked up)
That might happen because either your video chip is not up to the task or you don't have a the proper Video driver loaded for your video chip. Best if you start a new thread giving details on what you tried instead of posting in member intro about it. Gnome color chooser works ok though without any special needs.
Happy Trails, Rok