I recently picked up a Skil diamond masonry blade at Walmart for $15. Works fine for limited home use. If you're concerned about abusing your circular saw just make several shallow cuts instead of one deep cut.

Thanks...that's a *great* price, 1/3 or so the cost at Lowely's or Home Despot. Cheapest diamond/masonry blades were $35 and went up considerably from there.

So I decided to try just one with the ol' brick-set and hammer. Hey, it was good enough for several millennia of Egyptians, eh? and look what they built. (By now you may have guessed I'm rather parsimonious. Read: downright cheap....) The unit price on the "stone" is $3.50 versus less than a buck for bricks and pavers, so no great loss. But cutting a groove all the way around worked...well enough. It broke surprisingly long before I figured it would and didn't even have to whack it hard with the 3 pound lump hammer.

Cheers

I use an angle grinder and diamond blade ... cheap thang from Harbor Freight.