New Zealand Halloysite (Imerys, Matauri Bay)
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Clays
- Formula
- SiO₂ 49.5%, Al₂O₃ 35.5%, Fe₂O₃ 0.29%, TiO₂ 0.09%, LOI 13.8%
- Also called
- NZ Halloysite, New Zealand Kaolin, Halloysite Kaolin (NZ), NZCC Halloysite Premium, Kaolin New Zealand
- Made by
- Imerys (New Zealand China Clays), Matauri Bay, Northland, New Zealand
- Sold in
- AU, US
- Similar materials
- Grolleg China Clay , China Clay
- Source
- Imerys Tableware, Halloysite (Premium and Filtercake) typical values brochure (archived) (2006-04)
Very white, low-iron, low-titania halloysite (a kaolin-group clay) separated from altered rhyolite at Matauri Bay; used for translucent porcelain and very clear glazes. Sold in Australia by Walker Ceramics (BA139) and in the US as 'Kaolin New Zealand'.
Oxide analysis and unity formula
Glazecalc has the analysis of New Zealand Halloysite (Imerys, Matauri Bay) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of New Zealand Halloysite (Imerys, Matauri Bay) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
New Zealand Halloysite (Imerys, Matauri Bay) has no flux oxide, so its unity contribution is per formula as written.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| SiO₂ | 49.5 | 0.824 |
| Al₂O₃ | 35.5 | 0.348 |
| Fe₂O₃ | 0.29 | 0.002 |
| TiO₂ | 0.09 | 0.001 |
- Equivalent weight
- 100
- Fired weight
- 86.2
- Loss on ignition
- 13.8%
The equivalent weight is the grams of New Zealand Halloysite (Imerys, Matauri Bay) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Kaolin-group clay with fine tubular particles; the parent rock is quartz and cristobalite and traces may remain (the brochure's XRD shows both). Avoid breathing the dust.
Use it in a recipe
Add New Zealand Halloysite (Imerys, Matauri Bay) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.