Primary standard
NOTES: Homogeneous, but stay away from cracks.
 |  |
| Position | 61 |
| Mineral | Enstatite |
| Sample Name | En |
| Type | Pyroxene |
| Nominal formula | MgSiO3 |
| Supplier | Cannon Microprobe, Seattle, WA |
| Source | Sri Lanka. |
| Original reported analysis | Harvard oxygen standard |
| Composition quality | Primary standard |
| Comments | Harvard analysis modified very slightly to better fit stoichiometric constraints. This must come from a strange rock. |
| O Mg Al Si Ca Fe | 47.79 24.06 0.98 26.99 0.08 0.1 |
