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Manganese Oxide

Pyrolusite, Manganese (black)

Chemistry MnO 81.480

Volatiles LOI 18.520

Significant Temperatures

• 1785C: Melts

Links to Other Materials

• Manganese Dioxide - Unspecified
• Manganese Granular - Unspecified
• Cache

Hazards

• Manganese

Miscellaneous

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

Notes

Manganese monoxide is fine particle material derived from a variety of ores including mainly pyrolusite but also braunite, hausmannite, manganite, polianite, psilomelane, rhodochrosite, rhodonite, and was (mined in west Africa, Cuba, Brazil, USSR, India). Amethyst is manganese stained silica.

Glazes and bodies that employ manganese dioxide below its conversion temperature of 1080C (to MnO, a flux) will fire black and purple colors. In glazes, it will behave in a refractory manner, stiffening the melt (See MANGANESE DIOX. MnO2 for more information).

Above 1080C, half of the oxygen disassociates to produce MnO, a flux which immediately reacts with silica to produce violet colors in the absence of alumina, browns in its presence. Manganese browns have a different, often more pleasant character than iron browns.

If manganese is being used in glazes fired below 1080C, then it should be considered as composed of 100% MnO2, if above it should be taken as 81.5 MnO and 18.5 LOI.

Manganese dioxide is the key to Rockingham brown wares which are made by employing about 3% iron oxide and 7% manganese in a transparent lead glaze of a recipe such as: Feldspar 28, Kaolin 14, Flint 4, Lead bisilicate 40, Whiting 4.

Because to the expulsion of oxygen at 1080, glazes using manganese should avoid this temperature range to reduce the chance of blistering and ruining of the glaze surface.

Manganese oxides can occur in a number of less common forms: (i.e. Mn2O3 (manganese sesquioxide) melts at 1080C, Mn3O4 melts at 1700C, and Mn2O7 at less than 100C).

(Richard Willis)

Element, with the symbol Mn and atomic weight of 54.93
Of general use for clays and glazes as a colorant: from tan to purple to black, depending on companion colorants and firing conditions. see colorants
water solubility & fusion ºC
— dioxide — insoluble — 1100
— carbonate — insoluble — discomposes
commonly used forms
— oxide (manganous) MnO
— pot. permanganate KMnO₄
— dioxide MnO₂
— chlorurium MnCl₂, 4H₂O
— oxide (manganic) Mn₂O₃
— sulfate MnSO₄, 4H₂O
— carbonate MnCO₃
— orthophosphate MnPO₄, H₂O

Linked Articles

• Creativity and Illness by Dierdre O’Reilly

  A story of one persons struggle with manganese toxicity

• Manganèse & Composés Inorganiques Toxicologie

  Manganèse & Composés Inorganiques Toxicologie - Edouard Bastarache

• Manganese Inorganic Compounds Toxicology - Edouard Bastarache

  Manganese can be very toxic, expecially with regards to inhalation of the fumes during kiln firing. This material must be treated with care.

• My Story of Manganese and Parkinsons: Jane Watkins

  A person story about manganese poisoning.

• Potters Manganese Toxicity by Elke Blodgett

  A story of one persons struggle to identify and deal with manganese toxicity

Suppliers

• American Minerals Inc
  
• Generic
  

Authors

• Tony Hansen (Owner)

XML

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<material name="Manganese Oxide" descrip="Pyrolusite, Manganese (black)" generic="0" rawmineral="0" searchkey="MnO" loi="18.50">
<families>
<family name="Colorant"/>
</families>
<oxides>
<oxide symbol="MnO" name="Manganous Oxide" status="" percent="81.480" tolerance=""/>
</oxides>
<volatiles>
<volatile symbol="" name="" percent="18.520" tolerance=""/>
</volatiles>
<references>
<reference name="seealso" reason=""/>
<reference name="seealso" reason=""/>
</references>
<hazards>
<hazard name="Manganese"/>
</hazards>
<temperatures>
<temperature temperature="1785C" notes="Melts"/>
</temperatures>
<suppliers>
<supplier name="American Minerals Inc" country="US" url="http://www.americanminerals.net" label=""/>
<supplier name="Generic" country="" url="" label=""/>
</suppliers>
<notes>
<note>Manganese monoxide is fine particle material derived from a variety of ores including mainly pyrolusite but also braunite, hausmannite, manganite, polianite, psilomelane, rhodochrosite, rhodonite, and was (mined in west Africa, Cuba, Brazil, USSR, India). Amethyst is manganese stained silica.

Glazes and bodies that employ manganese dioxide below its conversion temperature of 1080C (to MnO, a flux) will fire black and purple colors. In glazes, it will behave in a refractory manner, stiffening the melt (See MANGANESE DIOX. MnO2 for more information).

Above 1080C, half of the oxygen disassociates to produce MnO, a flux which immediately reacts with silica to produce violet colors in the absence of alumina, browns in its presence. Manganese browns have a different, often more pleasant character than iron browns.

If manganese is being used in glazes fired below 1080C, then it should be considered as composed of 100% MnO2, if above it should be taken as 81.5 MnO and 18.5 LOI.

Manganese dioxide is the key to Rockingham brown wares which are made by employing about 3% iron oxide and 7% manganese in a transparent lead glaze of a recipe such as: Feldspar 28, Kaolin 14, Flint 4, Lead bisilicate 40, Whiting 4.

Because to the expulsion of oxygen at 1080, glazes using manganese should avoid this temperature range to reduce the chance of blistering and ruining of the glaze surface.

Manganese oxides can occur in a number of less common forms: (i.e. Mn2O3 (manganese sesquioxide) melts at 1080C, Mn3O4 melts at 1700C, and Mn2O7 at less than 100C).</note>
<note>Element, with the symbol Mn and atomic weight of 54.93
Of general use for clays and glazes as a colorant: from tan to purple to black, depending on companion colorants and firing conditions. &lt;FONT SIZE=2&gt;see &lt;B&gt;&lt;I&gt;colorants&lt;/I&gt;&lt;/B&gt;&lt;/FONT&gt;
&lt;B&gt;water solubility &amp;amp; fusion &amp;ordm;C
&lt;/B&gt;&amp;#151; dioxide &amp;#151; insoluble &amp;#151; 1100
&amp;#151; carbonate &amp;#151; insoluble &amp;#151; discomposes
&lt;B&gt;commonly used forms
&lt;/B&gt;&amp;#151; oxide (manganous) MnO
&amp;#151; pot. permanganate KMnO&lt;FONT SIZE=2&gt;&lt;SUB&gt;4&lt;/SUB&gt;&lt;/FONT&gt;&lt;SUB&gt;
&lt;/SUB&gt;&amp;#151; dioxide MnO&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;&lt;SUB&gt;
&lt;/SUB&gt;&amp;#151; chlorurium MnCl&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;, 4H&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;O
&amp;#151; oxide (manganic) Mn&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;SUB&gt;
&lt;/SUB&gt;&amp;#151; sulfate MnSO&lt;FONT SIZE=2&gt;&lt;SUB&gt;4&lt;/SUB&gt;&lt;/FONT&gt;, 4H&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;O
&amp;#151; carbonate MnCO&lt;FONT SIZE=2&gt;&lt;SUB&gt;3&lt;/SUB&gt;&lt;/FONT&gt;&lt;SUB&gt;
&lt;/SUB&gt;&amp;#151; orthophosphate MnPO&lt;FONT SIZE=2&gt;&lt;SUB&gt;4&lt;/SUB&gt;&lt;/FONT&gt;, H&lt;FONT SIZE=2&gt;&lt;SUB&gt;2&lt;/SUB&gt;&lt;/FONT&gt;O

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

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