| Element | Wt % |
| Oxide | Wt % |
| B | 3.90 | | B2O3 | 12.56 |
| O | 53.8 | | | |
| Na | 2.95 | | Na2O | 3.98 |
| Mg | 0.003 | | MgO | 0.005 |
| Al | 1.21 | | Al2O3 | 2.28 |
| Si | 37.8 | | SiO2 | 80.8 |
| Cl | 0.060 | | Cl | 0.060 |
| K | 0.012 | | K2O | 0.014 |
| Ca | 0.01 | | CaO | 0.01 |
| Ti | 0.008 | | TiO2 | 0.014 |
| Fe | 0.020 | | Fe2O3 | 0.028 |
| Zr | 0.031 | | ZrO2 | 0.042 |
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| Sum | 99.8 | |
Sum | 99.8 |
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2 x 2 x 1.2mm prisms and uncut slices
National Bureau of Standards
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