[Rockhounds] Fun with Sodium Carbonate...

[jbacko]

Tim Jokela Jr. wrote:
> Basic crystal growing:
>
> Make a small amount of concentrated solution and let it evaporate, 
> forming seed crystals. Select the largest seed crystal, and suspend it 
> in a jar of supersaturated solution, via thin monofilament fishing 
> line and a popsicle stick or similar. Cover jar with cloth and a 
> rubber band. Keep in an area of constant temperature and humidity if 
> possible, and watch your crystal grow.
>
> This works great for the easy-to-grow things like alum, dunno if it 
> will work for your chemical.
>
> Mandatory safety message: protect your eyes, lungs, and skin when 
> messing about with chemicals.
>
> "Crystals and crystal growing" by Holden & Morrison is probably the 
> best book on the subject. Also a lot of info online.
>
> T
Sodium Carbonate (Washing Soda) readily makes lots of "stepped"  
crystals from ordinary evaporation of saturated solutions.  They will 
cover the bottom of the jar easily and can be broken out if desired. 
However, they will not last in open air as they dessicate and turn again 
into a white powder.  The same thing happens to copper sulfate, iron 
sulfate and sodium bicarbonate.  Bicarbonate is harder to make into 
large crystals.

But it is relatively easy to make the crystals; they just will not be 
stable. Borax will do the same thing, but more slowly.

Potassium permanganate makes nice monoclinic crystals.

The usual "stalactites" are made by growing silicates from sodium 
silicate (Water Glass) and coloring them with seed crystals of various 
kinds.
Copper makes blue, nickel green, zinc creamy-white,  etc.

 
john