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Ochre

Chemistry CaO 0.501 MgO 0.200 Al2O3 6.027 SiO2 25.113 Fe2O3 55.645 MnO 3.014

Volatiles LOI 9.500

Miscellaneous

• Family: Colorant
• Region: None
• Mined At: Unspecified
• Raw Mineral: Yes
• Generic: No

Notes

Used in engobes, underglazes, and overglaze decoration for tan, brown and brick red hues.

Note

(Richard Willis)

A ferric oxide earth with significant percentages of manganese and other metals that makes it quite suitable as an engobe to interact with an overglaze for “under-glaze” color; or to smoke-scorch before glazing in order to blacken the clay body. Traditional to celadons and aka, or “black body, red-glaze”, raku see iron earths, and the titled entry for yellow ochre
— yellow ochre: hydrated ferric oxide (Fe₂O₃ + H₂0)
— black, or “shadow”, ochre: hydrated FeO plus Mn
— red ochre: (“ruddle”) anhydrated ferric oxide (Fe₂O₃)

Suppliers

• Generic
  

Authors

• Tony Hansen (Owner)

XML

<?xml version="1.0" encoding="UTF-8"?>
<material name="Ochre" descrip="" generic="0" rawmineral="1" searchkey="" loi="9.50">
<families>
<family name="Colorant"/>
</families>
<oxides>
<oxide symbol="CaO" name="Calcium Oxide, Calcia" status="" percent="0.501" tolerance=""/>
<oxide symbol="MgO" name="Magnesium Oxide, Magnesia" status="" percent="0.200" tolerance=""/>
<oxide symbol="Al2O3" name="Aluminum Oxide, Alumina" status="" percent="6.027" tolerance=""/>
<oxide symbol="SiO2" name="Silicon Dioxide, Silica" status="" percent="25.113" tolerance=""/>
<oxide symbol="Fe2O3" name="Iron Oxide, Ferric Oxide" status="" percent="55.645" tolerance=""/>
<oxide symbol="MnO" name="Manganous Oxide" status="" percent="3.014" tolerance=""/>
</oxides>
<volatiles>
<volatile symbol="" name="" percent="9.500" tolerance=""/>
</volatiles>
<suppliers>
<supplier name="Generic" country="" url="" label=""/>
</suppliers>
<notes>
<note>Used in engobes, underglazes, and overglaze decoration for tan, brown and brick red hues.</note>
<note>A ferric oxide earth with significant percentages of manganese and other metals that makes it quite suitable as an engobe to interact with an overglaze for &amp;#147;under-glaze&amp;#148; color; or to smoke-scorch before glazing in order to blacken the clay body. Traditional to celadons and &lt;B&gt;&lt;I&gt;aka&lt;/I&gt;&lt;/B&gt;, or &amp;#147;black body, red-glaze&amp;#148;, raku &lt;FONT SIZE=2&gt;see &lt;B&gt;&lt;I&gt;iron earths&lt;/I&gt;&lt;/B&gt;, and the titled entry for &lt;B&gt;&lt;I&gt;yellow ochre&lt;/I&gt;&lt;/B&gt;&lt;/FONT&gt;&lt;B&gt;&lt;I&gt;&lt;BR&gt;
&lt;/I&gt;&lt;/B&gt;&amp;#151; yellow ochre: hydrated ferric oxide (Fe&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;O&lt;FONT SIZE=2&gt;&lt;SUB&gt;3&lt;/SUB&gt;&lt;/FONT&gt; + H&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;0)&lt;BR&gt;
&amp;#151; black, or &amp;#147;shadow&amp;#148;, ochre: hydrated FeO plus Mn&lt;BR&gt;
&amp;#151; red ochre: (&amp;#147;ruddle&amp;#148;) anhydrated ferric oxide (Fe&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;O&lt;FONT SIZE=2&gt;&lt;SUB&gt;3&lt;/SUB&gt;&lt;/FONT&gt;)&lt;BR&gt;

</note>
</notes>
</material>

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