I would do brick. Just pick something that blends well with the siding and roof.

Are you in a neighborhood? What are the chimneys within a 2 - 3 mile radius of you? Are there any property owners restrictions? Our POA prohibits brick...only stone is acceptable.

What is your foundation, brick or stone? I would match that.

Is this an actual masonry chimney or merely a chase through which a metal vent pipe is run? Brick requires a foundation in order to support it's weight, and if you are doing a solid masonry structure, that should have been factored into the foundation pour. Even if you are doing "just" a brick veneer cladding of a chase, that also needs to be factored into the home's structural elements. It will probably need a steel lintel to support the weight and reinforcement of the point loads under the lintel. Be sure that the builder has taken care of the structural elements here before worrying about colors!

Hollysprings - thanks for the response, it's not a masonry chimney so I'm choosing "just" a brick veneer. The builder asks me to pick out colours and that's what I do. I couldn't even pretend to know enough about building to ask him about the structure of the chimney to determine if it's going to be strong enough. Can't I just trust him? When they build it, I can keep my out for a steel lintel but I think checking for reinforcement of the point loads might be a bit beyond me.

Maybe it depends on what part of the country you are in. Here in the PNW you see a sided chimney/chase that matches the house siding. If you side it in stone or brick, and that does not exist anywhere else, it may look out of place.

It appears you are referring to real or simulated 1/2" thick "thin brick/stone" (not 4 inch thick "brick veneer/stone") applied to a roof top structure intended to simulate a traditional masonry chimney that most likely hides a gas fireplace vent or a wood burning fireplace chimney and its termination cap.

To help you choose what material to simulate, we would need to see the design of the house with an indication of the materials and colors. Obviously, red brick is the most common traditional chimney material. Siding is the material of choice of builder/developers for low budget apartments and condominiums; it would look out of place on a single-family home IMHO. If you want to save money use synthetic stucco on cement board. Stone would usually be appropriate for a Craftsman or Shingle Style house.

What gives these simulated chimney enclosures away visually is the absence of roof flashing since water that enters the enclosure must drain out onto the roof surface - sort of the reverse of a real chimney.

The only one I've done encloses a very large wood-burning fireplace vent and cap (shown below) on a Shingle Style house. It appears to be sitting on the roof instead of penetrating it but, fortunately, the base of it is not easy to see from the ground.

Razmatazzy - that was what I was sort of thinking but IRL I've never seen a chimney with siding on it - so I chose brick

Renovator8 - that's a very nice house and a very nice chimney. Yes, it is a 1" thick veneer of something I had to choose. I get what you mean about sitting on the roof - ours too won't be obvious from the ground - I hope. I did go traditional - reddish brick.

Thank you very much for sharing your opinions and helping me with this decision - I'm sure I'll be back.

I know you have made your decision, but I thought I'd let you know that POA stands for Property Owners Association. They "run" the neighborhood. They have certain "rules" about what you can and can't have in your yard, approve the exterior paint colors (you wouldn't believe the awful colors people can come up with), and fence styles. This is to keep continuity in the neighborhood. We must use natural stone. It's a mountain community and they want to keep a more rustic wooded atmosphere. Before we ever bought the lot, we got a list of the rules and agreed to them. Things are not all set in stone and the committee has been know to change their minds about the rules too.

And yes, they can sometimes be PITA too. They want to monitor the size of trees that can be taken down in your yard...a certain diameter, but they have changed that over the years too. (The size got bigger.) Now they allow log cabins when at one time they weren't permitted. Since cable TV doesn't run out there, they started to allow satellite dishes.

I won't go into all their rules.

Aaah, all I could think of was power of attorney.

And, wow! I had no idea.

Well, you really do learn something new every day.