All three are unglazed. There is no coating on the surface, so the color you see is the body of the tile itself, and every piece carries the marks of how it was made and where it sat in the kiln.
Saltillo and Lincoln come from the Saltillo and Tecate regions of Mexico. Saltillo runs light: warm buff, pink sand and light clay tones, straight edge, offered in both Super and Regular. Lincoln is the deeper brown, sold in some markets as Tecate, and it comes in Regular only, with rounded edges and a pillowed face.
Antique Terra Cotta is a different proposition. It is vintage and reclaimed French tile, worn smooth in place long before it reached us, for projects that want age you cannot manufacture.
All three need sealing to protect against stains and the elements.
