• Question: can you make rocks bigger and stronger or soft and easy to mush or break

    Asked by chewyoda007 to Alexander on 20 Jun 2013.
    • Photo: Alexander Munnoch

      Alexander Munnoch answered on 20 Jun 2013:

      Awesome question chewyoda007, guessing you’re a Star Wars fan as well!
      Simple answer is… yes to all of the above!

      Nature already does this through various processes such as solidifying lava flows from volcanos and erosion of cliff sides by sea water.

      Humans could also do this but to do so we copy nature (as scientist do).

      It is possible to make rocks crude (limestone, sandstone etc..) and precious (such as zeolites sapphires, diamonds etc…) and this is commonly done by copy the way nature do it so…

      Three common ways (there are more) of making rocks (glasses and crystals included in this) are by:
      Precipitation: where a solid forms out of solutions https://en.wikipedia.org/wiki/Precipitation_%28chemistry%29

      High temperature-high pressure methods:
      http://en.wikipedia.org/wiki/Hydrothermal_synthesis
      Including hydrothermal which can include heating up sealed containers with different salts and water (like a bomb) but the conditions inside mimicthe conditions at hydrothermal vents on the sea floor where rocks grow naturally.

      CVD (Chemical Vapour Deposition):
      https://en.wikipedia.org/wiki/Chemical_vapor_deposition

      In terms of making them softer there are loads of different ways of doing this.
      Chemically: by dissolving them down in water/acids/alkalis.
      Physically: Sound, lasers, radiation.

      Chemically is generally favoured and is employed ALOT in the refining industries where they try to get pure metals (and their oxides) from ores (rocks with a high amount of the metal in them).
      The Bayer process area good example where aluminium is refined from bauxite.

      Aluminium is dissolved out of the bauxite ore using sodium hydroxide (strong alkali) and after heating makes aluminium oxide – the main thing in precious gems like sapphires.

      However, dissolving out only a bit of the ores does produce alot of waste, for aluminium it is Red Mud. I spent time in India working on possible uses for this waste (because there is an awful lot of it).

      Hopefully this answers your question and if you’ve got any more pleas elet me know.
      Alex

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