Finishes 

Matte: This finish is unpolished for a rough and matte surface. 
Polished: This finish is polished for a shiny and smooth look and feel. 

*Results may vary depending on geometry and model detail.

Colors 

Bronzed-Silver: A metallic silvery color with a bronze tint. 
Gold: Thin layer of 24K gold plating that will wear with handling 
Nickel: Thin layer of nickel plating providing a shiny silver gray color than can darken over time with exposure to skin. 
Bronze: This finish gives the material a brown antique bronze look 
Black: The black finish gives the material a dark gray to black look 

To build steel models, special 3D printers deposit small drops of glue onto layers of stainless steel powder, one layer at a time, until the print is complete. We carefully remove these models from the printer. At this stage of the process, the objects are very fragile, similar to wet sand. The models then go through an infusion process that replaces the glue with bronze, creating a full metal product. Models are then processed to achieve your desired finish, sprayed with a sealant, and shipped to you.

The bronze infiltration process requires the addition of supporting stilts that are broken off and polished away after infusion. This can create small, round marks on the final product that appear smoother and more polished than the rest of the product.

https://www.shapeways.com/materials/steel