Action:
On display are several large crystals in a dish.

You Need:
Ordinary alum (potassium aluminum sulfate).

Why:
Crystals are seen to grow over a period of days.

How:
Make a saturated solution of alum by heating the salt in a very small volume of water. Cool and allow crystals to settle. With a spatula or small knife remove some of the best crystals to a large dish. Again make a saturated solution of alum and pour this cool solution over the crystal. The crystal will grow and in a day or two should be removed and again placed in a fresh saturated solution. Repeat this procedure many times and eventually you will grow a large crystal.
You must move the crystal around in many positions in order to get an even growth of hces.

Suggestions:
Make a saturated solution of copper sulfate by heating 50 grams of salt in 100 ml. of water. Cool and suspend a crystal of copper sulhte in the solution. This crystal, hstened with a string to a ring stand, will continue to grow. After a day or two, remove the solution and replace it with a fresh saturated solution of copper sulfate. Repeating this procedure for days and weeks will eventually produce a giant crystal.