When a ruby is used

Ok so a ruby adds a legend affix, but before I use one I was hoping someone could tell me if it gives you a selection of affixes to choose from like obsidian does? Or does it just stick you with a random affix?

It gives you 5 affixes if im not mistaken, but beware, sometimes even with those 5 affixes the one you are aiming for is not there.

Thank you. Yeah obsidian is like that so it was the best I could hope for.