Do you know anyone who lives in an area with reddish soil?  I've seen it in Western North and South Dakota and in Oklahoma as well.  (I think it's due to a high scoria content?)  Some red earth-bound dirt and rocks might do the trick if you can find a donor.  

Edit- I just did some looking and the red soil in Oklahoma apparently is more clay like and may not work as well as the rocky stuff in the Western Dakotas...?

Red pumce. These pictures is a Mars landscape and the other is red pumce (lava).

Hobby Lobby sells bottles of colored sand that might work. I would not use this sand in a permanent diorama but I think it would work in a temporary science fair project.

Most pet stores have coloured sand for lizard habitats.  I used to work for one years ago but I remember there being a few desert versions in red and reddish brown that might work.  Might be a bit expensive for a class project.

Gordy

Woodland Scenics is a company that specializes in all sorts of "ground cover", it sells a red oxide sand material that is easy to work with. Most good hobby shops stock their product, especially train shops. Good luck.  

Hot of the BBC web, the real thing...   from the.... err... Smithsonian, 

www.bbc.co.uk/.../science-environment-25632383

They'll care more about a good looking Rover than an accurate Martian surface. Invest time on the model, spraypaint a sandy rough surface orangey-red and call it a day.

Thanks Guys!-- I was more looking for a material I can put on a piece of plywood that will harden  (sculpting Clay or styrofoam?) then spray painting a rust color -- paper models are fun, but I'm aching to get back to my Sopwith Pup!! Let me know if anyone wants a link to the paper model --

Regards,

Dog

Hello again -- looks like the product Im looking for is called 'sculptamold' -

Dog

elass0wyp0

Most pet stores have coloured sand for lizard habitats.  I used to work for one years ago but I remember there being a few desert versions in red and reddish brown that might work.  Might be a bit expensive for a class project.

Gordy

OTOH you will have enough sand for every DAK kit you build. assuming a relatively flat surface cheap modeling clay works well. the trick is to get cheap artist acrylics (and the cheapest the better) that is close to the material color and paint the clay. just slop it on and spread it around. i used blue clay once for RR tracks and put down gravel and it was not fun trying to fill or paint the spots i missed.

liquidtex would work too. you can actually mix the material and paint before putting it down

Hollow 'doughnut' rock appears in Mars rover's path

After a decade on the Martian surface, you might think that NASA's Opportunity rover has seen it all. But just before the 10th anniversary of the rover's landing, its operators got a surprise treat: a weird rock "materialised" right in front of the rover's wheels.

The image on the left was taken by the rover's panoramic camera on the 3528th sol, or Martian day, of the mission. The image on the right is of the same spot 12 days later. It shows an additional rock about the size of a doughnut that seems to have appeared out of the blue.

"We just all went, 'Huh? What's going on?'" says rover project scientist Matt Golombek at NASA's Jet Propulsion Laboratory in Pasadena, California. "It's very interesting when you see a rock that wasn't there before. It's a fun surprise."

Nicknamed Pinnacle Island, the rock has a raised ridge and a hollowed-out centre. The rover team is not sure where it came from, but they suspect it could have been ejected by a nearby meteorite impact – or dropped there by the rover itself. "It's most likely just a rock that was picked up and kicked by the wheel, which clicked it over to a new spot," says Golombek.

dogzilla17

Hello again -- looks like the product Im looking for is called 'sculptamold' -

perhaps a combination of sculpta and red sand over it's surface to give correct texture/color?

I work out in the Australia outback and I recon the closest thing to that colour would be the outback sand. Google it and you will see my point.

Cheers Leo