Longquan Zijin Soil, Gaojitou
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Clays
- Status
- Historical
- Formula
- SiO₂ 66.93%, Al₂O₃ 18.01%, CaO 1.23%, MgO 0.51%, K₂O 5.23%, Na₂O 0.45%, Fe₂O₃ 3.11%, TiO₂ 0.45%, MnO 0.08%, LOI 4.47%
- Also called
- Gaojitou Zijin soil, Zijin soil, 紫金土
- Similar materials
- Redart
- Source
- He Z., Zhang M., Zhang H., 'Data-driven research on chemical features of Jingdezhen and Longquan celadon by energy dispersive X-ray fluorescence', arXiv:1511.07825 (2015), Table 6 (2015)
Historical: an iron-rich local clay (紫金土) from Gaojitou village in Dayao, near the Longquan kilns in China, added to Longquan bodies for their iron and alumina; it is not sold outside China. This is one analysis, which the paper quotes from earlier Chinese studies. How it was dug and prepared is not in the source.
Oxide analysis and unity formula
Glazecalc has the analysis of Longquan Zijin Soil, Gaojitou as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Longquan Zijin Soil, Gaojitou that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| SiO₂ | 66.93 | 11.309 |
| Al₂O₃ | 18.01 | 1.793 |
| CaO | 1.23 | 0.223 |
| MgO | 0.51 | 0.128 |
| K₂O | 5.23 | 0.564 |
| Na₂O | 0.45 | 0.074 |
| Fe₂O₃ | 3.11 | 0.198 |
| TiO₂ | 0.45 | 0.057 |
| MnO | 0.08 | 0.011 |
- Equivalent weight
- 1015.24
- Fired weight
- 969.85
- Loss on ignition
- 4.47%
The equivalent weight is the grams of Longquan Zijin Soil, Gaojitou that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Contains crystalline silica; avoid breathing the dust.
Use it in a recipe
Add Longquan Zijin Soil, Gaojitou to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.