| Title | Ferrous oolitic (red) limestone | 
| Description | This is a polished sample of red limestone.  The red color is due to the presence of hematite, Fe2O3.  The rounded shapes apparent on the polished surface are oolites.  The specimen is about 8 cm across. | 
| Photographer | Twyla Baker. 2001-06-11. | 
| Collection | University of North Dakota Mineralogy Collection. | 
| Key words | limestone, oolite | 
| Tech details | 1010 KB. Hand specimen. Fujifilm FinePix S1Pro digital camera; 60mm AF Nikon micro lens. | 
| GeoDIL number | 693 | 
  |