OK, it's agate, semi-precious quartzite stones set into a form in which resin is poured, hardened and polished.

Semi-precious stones set in form.

Source: Minerals.net

Agate in forms ready to be polished.

Although blue seems the most popular colour, agate comes in a range of colours.

Green Agate panel.

Red agate.

Large finished panels are often imported from Brazil and China, then cut if necessary, highly marked-up and re-sold in N.A.

Indeed!

(The featured home is listed for C$11.8 million.)

I'm now thinking of it more as accent pieces in our planned largely monochromatic grey international style home. Will leave it to our colour coordinator's judgement.

I love blue, but don't think those look particularly good and wouldn't like having the amount of visible resin that those counters have between the geodes. Much prefer the look of Azul Do Mar quartzite for a blue stone counter.

I've never seen it in person but suspect I'd prefer it on a vertical than horizontal plane. I was looking at pink agate drawer knobs for my bedside chest. I think the colours are so pretty!

I have the brown agate in my master bathroom, coffee bar area and what was left over was big enough for the countertop of a small bathroom vanity. I even used one cutout in the peak of the crown molding in my bathroom. I saw it in the granite showroom and it just sang out to me. All the personnel there laughed at me as I ran over to it, splayed myself out over it and yelled, "MINE!" They held it for 8 months until my addition was ready and they told every customer who walked in the story.

I threatened to go there while they were cutting it and stand there with a net underneath to catch all the chips and make jewelry. ( I didn't but I still wish I had. )

I have 2 small agate tables...blueish, beigeish, grayish. They are absolutely beautiful and they let light shine through, they are interesting...but they are small, and that is why they work. In my opinion, agate would be way too busy as a whole countertop (unless you have an ultra contemporary kitchen and it is the only show stopper)...but yes, I love them as drink tables.