Are these really rocks? I think so; they have every important attribute of rocks, except that they aren't natural. They're better than natural. See What Is a Rock? for more discussion.
|Adobe Arch||Adobe Bricks||Lime Kiln||Inside a Lime Kiln|
|Mortar in a Stone Wall||Plaster Frieze||Plaster and Brick||Brick and Mortar|
|Brick Tile||Concrete Sidewalk||Sidewalk Cross Section||Aggregate in Concrete|