??

Won't anything still be dusty, unless you eliminate the dust?

Do you have a picture of the coffee table? You could maybe turn it into an ottoman depending on the shape. Add some foam, dacron wrap and staple fabric around. I've seen this done on a few blogs.

"Won't anything still be dusty, unless you eliminate the dust?"
It will still be dusty but you won't see it as much depending on what you do.

Here are a couple of photos. I realize that dust would still be on the surface but not so noticiable when the sun shines into the room. I could dust this every hour and it would still look dusty!

I think the only thing that would look ok in that ornate table would be some light colored marble. You'd need it to be very thin, though, the same thickness as the glass, so it might be difficult to find that.

Check with stone masons and tile places to see if they can custom cut for that size. I can't think of anything else that would work.

How about a contrasting wood with an interesting grain? A furniture refinisher or good carpenter could probably do it. (I can't picture tile at all...and slate seems too "rustic" for that ornate table).

Here is a link that might be useful: Exotic Woods

Wood insets although the finish may be difficult to match; stone insets, or leather covered insets. You can get leather or faux leather table top material in some woodworking/furniture making catalogs.

What a beautiful table. I would hate to change it....would a small round peice of cloth or a doily of some kind to cover the top be feasible? Or a round tray of some kind to put on top to cover most of the glass.