| The prominent basement rocks of the Brumado area are Precambrian in age and consist dominantly of gneisses, schists, and amphibolite. |
| It grades into a manganese-rich ilmenite that ultimately replaces the spinel phase near the transition to the garnet amphibolite. |
| The Archaean Baidrag complex, composed of tonalitic gneiss, granulite and amphibolite, with minor marble and quartzite, has been interpreted as a microcontinental block. |
| The specimen was taken from a pegmatite dike at its contact with an amphibolite. |
| A uniform, regionally concordant layer of amphibolite with occasional ultramafic pods, termed the Sta Amphibolite, overlies the Sta Series. |
| Specific rock names that record both the parent rock and its mineralogy are relatively rare, but include eclogite, blueschist, and amphibolite. |
