Gravity is Optional
Crystal Growing

Many chemicals found in the home (or at least in a grocery store) can be used to grow crystals. The following are a few common examples. These chemicals all have the ability to dissolve in water at room temperature, and the purity necessary to grow crystals.

Purity is not a requirement for growing crystals. One of the ways to purify a mixture of various substances is to grow crystals. The crystals are the pure substance, and the gunk (whatever else was present) gets left behind. However, this does not always work - sometimes you might get a combination of 2 types of crystals which are hard to separate mechanically (such as picking them out by hand). In other cases, crystals simply won't grow.

Studying crystals is an important part of physics, chemistry, and geology. Much of what we know (or at least, think we know) about the universe come from their study.

Coal Garden

We are not talking about growing coal - - but a crystal garden that grows on coal.

In the past, homes used coal for heat - therefore, it was easy to obtain. However, any porous substrate will work - paper towels, sponge, whatever. The idea is to use something with good capillary action and lots of edges where water will evaporate - because that is where the crystals grow.

An old recipe is to start with a lump of coal. Add twigs (support) and Spanish moss (good evaporation). Add too much salt to some water, you want a super saturated solution. In theory, that is all you need. However, the traditional recipe also includes bluing and ammonia - like coal, both were common in the Depression.

Things with lots of pores will help the water evaporate faster. Some rocks have lots of pores - coal and limestone work. Paper towels are good, but need a support so they have an edge a bit above the solution..

A few drops of ammonia will reduce the surface tension so the water flows better and evaporates faster.

Mrs. Stewart’s Bluing is a colloidal suspension of extremely minute particles of blue powder (Ferric Hexacyanoferrate). When white clothes are washed a lot, they tend to turn yellow. In the past, adding an inert blue substance (bluing) to the wash made them look whiter simply because they reflected more blue light. In the store, I found some next to the bleaches. It even had a red and yellow sign on it

False coloring is not a requirement, but many people like to add a few drops of food coloring. Don't put these in the bulk liquid - put them on a dry part of the garden.

Because they grow so fast, the crystals in a coal garden tend to be quite small. If you put a super saturated solution in a sealed jar, you will get larger crystals. It may take a month .. or two .. but the results can be impressive.

Some substances, like sugar, won't crystallize in a sealed jar. (Sugar plus water just becomes syrup.) In these cases, there needs to be something for the water to evaporate from. The common suggestion is a piece of string tied to a stick placed over the top of the jar. Do not seal the jar, just leave the top off. As long as the string is below the top, the rate of evaporation will be slower and larger crystals will form. Speed is the key.

When studying rocks, you will see lots of crystals. For igneous rocks, the longer it took for the original liquid to cool, the larger the crystals.

Speed is the key. This is because crystals both grow and dissolve at the growth surface. When conditions are right, there is a lot more growth than dissolving, and the crystals remain small. (Rapid cooling in the case of igneous rocks, rapid evaporation in the case of water soluable salts.) However, when crystal formation is slowed down, the small crystals still form, but they are more likely to redissolve. The large crystals are just a little bit harder to redissolve. Mostly, this is related to the difference in surface area and the fact that edges grow and dissolve faster than surfaces. As a result, if there is enough time, all the small crystals eventually redissolve and you only get large crystals.

Author: Robert Clemenzi
URL: http:// / CrystalGrowing.html