The next up on my License Plate Geology is "Stone"
1. A general term for rock that is used in construction, either crushed for use as aggregate or cut into shaped blocks as dimension stone.
2. One of the larger fragments in a variable matrix of a sedimentary rock.
3. A stony meteorite.
4. A cut and polished natural gemstone; a gem or precious stone.
(Definition courtesy of the Dictionary of Geological Terms, 3rd Ed.)