[Boromir88]

Saruman certainly had the knowledge to attempt to create a Ring of Power, so I don't doubt that he could make one and that it would have some kind of power.

Of course there is no difinitive answer to it, I think. Both sides can be supported and argued by using the same quotes, just a matter of how you interpret it.

It's clear that Saruman did have a Ring, as Gandalf remarks in The Council of Elrond. Which means either:

1. Saruman had made actually made this ring, with the knowledge that he gained from studying them.

2. It was one he found, came across, and he wore it to boost his arrogance as being like Sauron.

Personally I believe it's Number 2, as there is I think way too slight evidence to prove Saruman had made his own ring. In an early draft there is this quote:

"He wore a ring on his finger...

...and it was at one time rumoured that he had come near the secret of their making."~Home VII Treason of Isengard

This reference which may lead to reader's implying that Saruman had made his Ring is removed from what finally appears in The Lord of the Rings. What appears in the Council of Elrond (the published version) is:

'He wore a ring on his finger.'

'For I am Saruman the Wise, Saruman Ring-maker, Saruman of Many colors!'~The Council of Elrond

There is no difference with the first quote, but Tolkien took out a possible reference to the reader believing Saruman had learned how to create a ring with...

'Saruman Ring-maker'

At first look, this may be solid proof that Saruman created his own ring, but let's look at it a bit further. Notice the capitilization, it is a title, it is a name. If we look at A Shadow of the Past, Ring-maker is actually a name given to Sauron:

'Behind that there was something else at work, beyond any design of the Ring-maker.'

So, Ring-maker is actually a name Gandalf gives to Sauron. And Saruman takes up this title he is now Saruman Ring-maker. Admittingly you can interpret this a few ways, you can believe that Saruman created his own ring and took up a title given to Sauron.

Or, you can think that Saruman just wanted to appear like he was Sauron and he was boosting his pride in that he was emmulating Sauron. He found a Ring, and now he was Ring-maker, symbolizing that he was Sauron. And perhaps jealousy has a factor in this matter as well. We find out that Saruman knew Gandalf had been given one of the Elven-Rings and became jealous because of this:

'And the Grey Messenger took the ring , and kept it secret; yet the White Messenger (who was skilled to uncover all secrets) after a time became aware of this gift, and begrudged it, and it was the beginning of the hidden ill-will that he bore the Grey,which afterwards became manifest.'~The Istari

I think it was a combination of Saruman's jealousy that Gandalf had a ring, and he didn't, and the fact that he was trying to emmulate he had the power of Sauron that feuled him to finding a Ring and taking up the name as Saruman Ring-maker.

I think it's just questionable, and we can't definitively say either. Personally, I think the text is way to slim and circumstantial to believe that Saruman created the Ring because of the reasons given above.