| Asbestos bodies are asbestos fibers that have been coated with an iron-rich, proteinaceous concretion. |
| Figure 6 shows examples of both a complete concretion and a polished cutaway section that shows the radial structure and dark center. |
| Limited dolomitization of the calcite around the edges of the fossils and in the matrix of the concretion occurred at a later stage. |
| The concern with material concretion begins with Bernstein's title, With Strings. |
| The concretion matrix is dominantly an interlocking mosaic of calcite, ferroan dolomite and quartz. |
| Recently, one of us saw a bin of silicified barite concretion fragments in a Utah rock shop that were being sold as cycad specimens. |
