| Element | % |
| Oxide | % |
| k0963-1 |
| |
| |
| O | 40.62 | | | |
|
3mm and smaller black prisms
|
|
National Bureau of Standards
|
| |
| Mg | 0.34 | | MgO | 0.56 |
| Si | 21.96 | | SiO2 | 46.98 |
| P | 0.33 | | P2O5 | 0.76 |
| Ti | 0.32 | | TiO2 | 0.53 |
| Cr | 0.31 | | Cr2O3 | 0.45 |
| Ni | 0.33 | | NiO | 0.42 |
| Zn | 2.95 | | ZnO | 3.67 |
| Ge | 30.39 | | GeO2 | 43.78 |
| Zr | 0.61 | | ZrO2 | 0.82 |
| Eu | 0.95 | | Eu2O3 | 1.10 |
| Th | 0.06 | | ThO2 | 0.07 |
| U | 0.16 | | UO2 | 0.18 |
|
|
|
| Sum | 99.3 | | Sum | 99.3 |
|