Crystals Can Grow    
                  
Growing Copper Sulfate Crystals
    Cochise College                                     

    Geology Home Page               

    Roger Weller, geology instructor ( wellerr@cochise.edu )
    last edited:  12/22/15   
    copyright 2015-R.Weller


   

 

        One of the very best chemicals for growing crystals is copper sulfate.  The
   only trouble with it is that is a
poisonous chemical compound.  Because of its
   poisonous nature, it has been used to kill tree roots in sewers.  A solution of
   copper sulfate is simply flushed down the toilet to kill tree roots.  In some cases
   this treatment turned out to cause more harm than good.  If the sewer pipes were
   made out of cast iron, the copper sulfate reacted with the iron, causing the iron to
   go into solution and precipitating tiny copper crystals in the process.  The tiny
   copper crystals were then usually washed away by subsequent flushing, but
   larger holes were created in the iron pipes that allowed larger roots to grow in the
   pipes at a later time.  Because of its use in killing tree roots, copper sulfate can be
   purchased in hardware and plumbing supply stores.
 

        So, if you wish to grow copper sulfate crystals, you must seriously emphasize
   the fact to your students that the chemical is
poisonous and that they must wash
   their hands after working with this chemical.  One factor helping in the safety of
   using this material is that even in dilute solutions it has a very bad taste.
 

       Copper sulfate responds well to the supersaturation technique is which you
   dissolve as much copper sulfate as possible in boiling hot water and then allow it
   slowly cool
.  Nice crystals can form in as little as 4 to 6 hours. Warning!  Copper
   sulfate chemically reacts with iron, so do not try try to warm a solution in a stainless
   steel kettle. 
One of the videos listed at the bottom of this page shows crystals of
   copper sulfate that were grown in four hours by the supersaturation technique.

 

        The best, sharpest and clear copper sulfate crystals form by the evaporation
   process.  Just prepare a saturated solution (in which you have dissolved as much
   copper sulfate that you can in water).  Carefully and slowly pour this solution into
   a clean glass or plastic container, making sure that any undissolved crystals are
   left behind in the first container.  Any crystals that are transferred to the new
   container will become seed crystals that will trigger off the formation of crystal
   growth.  Too many seed crystals will produce myriads of tiny copper sulfate
   crystals instead of just a few, large crystals.  Even the process of pouring the
   saturated solution from one container to another can trigger the production of
   large numbers of seed crystals.  Carefully pouring the solution slowly and
   avoiding any splashing will reduce the chance of creating extra seed crystals.

 

      

        The solution on the right was allowed to evaporate for two weeks and it
   produced the following crystals.

 

   
    a nice cluster of copper sulfate crystals


  
   The deep beautiful blue color makes copper sulfate a popular chemical for
   growing crystals.


  
   Copper sulfate produces Triclinic crystals.


  
   The triclinic shape of copper sulfate can be seen in this cluster of crystals.

 

        Copper sulfate crystals are somewhat strange.  Some crystals can hold their
   color for years with no change, while others dehydrate and turn into a white
   powder.

   

   This crystal  of copper sulfate is nearly twenty years old.  Note the white
   patches    where it is starting to dehydrate.


   

        Notice the fingerprints on this crystal of copper sulfate.  The crystals that have
   been grown at room temperature from solution are water soluble.  Moisture from
   your fingers can dissolve these crystals and leave finger prints on the crystal
   surfaces.  So, if you want to keep  your specimens shiny, don't touch the crystal
   surfaces.  The finger prints also indicate that some of the copper sulfate dissolved
   and now you have some copper sulfate on your hands.

 

   

        The attractive specimen above is also nearly twenty years old.  It was kept
   away from heat and light which is why it did not deteriorate.


 

     When copper sulfate forms naturally, it is known as the mineral chalcanthite.

   



  links on growing copper sulfate crystals

 
  How to Grow Copper Sulfate Crystals 

   VIDEO: 4 Hour Copper Sulfate Crystals
   VIDEO: My Biggest Copper Sulfate Crystal Ever
   VIDEO: Copper Sulfate Crystal


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