Secondary standard
NOTES: Homogeneous in the cobaltite areas (purple in the X-ray map). Stay away from the small grain of pyrite (green) and the yellowish areas, which is a different Fe-Co-As sulfide. No difference seen on the BSE image between the purple and yellow phases. It’s amazing that the two phases aren’t differentiated on the BSE image.
 |  |
| Position | 4 |
| Mineral | Cobaltite |
| Sample Name | Cob |
| Type | Sulfide |
| Nominal formula | CoAsS |
| Supplier | Cannon Microprobe, Seattle, WA |
| Source | Blackbird Mine, Joplin, Lemhi County, Idaho |
| Original reported analysis | Semi-quantitative analysis |
| Composition quality | Secondary standard |
| Comments | Blackbird Mine material contains up to 2% iron. |
| S Fe Co Ni As Sb | 19.33 1.75 32.2 1.49 45.02 0.23 |
