• Question: What do the terms mafic and felsic mean (minerals)?

    Asked by ellz13 to Angus, Christian, Hannah, Laura, Simon on 18 Jun 2013.
    • Photo: Hannah Bentham

      Hannah Bentham answered on 18 Jun 2013:

      Mafic are silica based minerals cotaining heavier elements such as iron and magnesium. e.g. olivine and pyroxene
      Felsic are silica based minerals containing less heavier elements, and more lighter elements such as oxygen, aluminum and potassium. e.g. quartz

    • Photo: Simon Holyoake

      Simon Holyoake answered on 18 Jun 2013:

      Nice answer from Hannah

      I had to look this one up 😉

    • Photo: Christian Maerz

      Christian Maerz answered on 18 Jun 2013:

      To add to Hannah’s answer: The terms mafic and felsic are actually derived from old abbreviations of the combination of respective elements mostly contained in mafic and felsic rocks. Mafic = magnesium and iron (Fe). Felsic = silicon and iron (Fe). Often, in the field, you can distinguish mafic and felsic simply by their colours, mafic tending to be much darker than felsic.

    • Photo: Laura Roberts Artal

      Laura Roberts Artal answered on 19 Jun 2013:

      Both Chris and Hannah have done a great job to explain this! Mafic and felsic rocks are igenous, meaning they come from volcanoes and often you can define a volcano by the types of rocks it produces.

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