[Rockhounds] More fun with NaCO3 crystals...

[jbacko]

Brett Allen Johnson wrote:
> jbacko, so what you are saying is to make a super saturated solution of NaCO3+H2O and let evaporate to grow well formed crystals? Is this like growing epsom crystals? I will give it a go and report back after I get some success. Thanks, Brett
> ps. Do you have any other mixture/growing tips you would like to share with the Group?
>
>   
The main things to do are:

    1. Use a very clean glass jar (like a mayonnaise or Ball canning jar).

    2. Use clean and soft water; distilled water is easily available.

    3, Saturate your solution with a moderately warm but not hot 
temperature (~150-160 F.) It doesn't hurt to boil the solution but that 
tends to put  too much material in solution and make it a bit unstable 
for large xtal growth. Make certain that ALL of the material is dissolved.

    4. Cover the solution such that evaporation can take place but NO 
dust particles can get into the jar.

    5. Put the jar in a dark, quiet place and let it sit until it does 
it's thing. Don't be in too much of a hurry to find out what is going 
on; any disturbance will cause rapid growth of small crystals. This may 
occur despite your best efforts.

     6. After a week or two, you should have some nice crystals. Try it 
first with copper sulfate as it is very easy to grow into large 
crystals. Then repeat the operation using one of the larger crystals as 
a seed, It has to be large enough to not completely dissolve in the warm 
water solution. Be absolutely certain that all of the  material except 
your seed is in solution. After a few days you should have one (or a 
few) large xtal(s).

    7. Your results will vary according to the materials and conditions. 
If you live next to a railroad or airport, for instance, you are 
probably going to get a lot of periodic vibration, which is not good.

    8. Copper Sulfate is available at place like pool or septic 
suppliers as it is used as an algaecide. Sometimes one can find 
relatively pure iron sulfate as a soil conditioner. Epsom salts is at 
the pharmacy (and sometimes small quantities of U.S.P. copper sulfate). 
Nitrates can be found in quick-dissolving fertilizers, but they are 
usually too mixed up and of too poor a quality to be of much use. 
Nonetheless, one can "refine" them by successive evaporation and 
fractional separation. Nickel Sulfate will have to come from a chemical 
supply house as far as I know. Sodium Thiosulfate used to be commonly 
available as a photographic fixer, but silver-based photography is 
rapidly disappearing and it may be tough to find. It can be grown as 
relatively large crystals if the solution is not too hot or too strong 
to begin with; once it supersaturates, any shock will crystallize the 
whole mass as fine crystals (as mentioned above). Washing Soda, 
Bicarbonate of Soda, and Borax are all at your local supermarket. 
Washing Soda does not work well with seed crystals; usually one gets a 
mass of relatively large interlocking "stepped" crystals no matter what 
one does. Agricultural sulfur can be dissolved in something like toluene 
and crystallized, but it is not an operation for the careless or foolhardy.

    9. Sources? When I was young, we could write away to all the 
advertisers in Chemical and Engineering News for samples; I filled up a 
whole basement lab that way. I don't think that is allowed anymore.  
Nuts!  I guess your local high-school or college chemistry teacher is as 
good a source of info on where to get things as any.

    10. Have fun. Crystals are neat! (At least Nature thinks so.)



 
john