Potassium Aluminium Sulphate (Alum)    

Potassium Sodium Tartrate Tetrahydrate

Sodium Chlorate

Potassium Ferricyanide

Strontium Formate Dihydrate

Calcium Copper Acetate Hexahydrate

Potassium Aluminium Sulphate

(Alum or Potash Alum – Colourless Cubic system)

Require: Potassium Aluminium Sulphate

Alum grows well, offers no special problems and is therefore the best choice for a first attempt at crystal growth. If the crystal grows too quickly, it will have many veils and look milky. If it does, in our second attempt reduce the [B] quantity The easiest way to make this change is first to harvest the veiled crystal and any debris in the jar, dry them, and weigh them. If the veiled crystal and debris together weigh more than the [B] quantity, your ‘saturated’ solution was ‘super-saturated’ A convenient way to remake it is to break up the veiled crystal, giving it extra surfaces, and put it back in the solution. Belying theses crystal fragments remain for several more days than you did the first time, you can make sure all the extra material deposits. If the crystal and debris weigh less than the [B] quantity, that quantity is too large to give satisfactory results at your growing temperature. Reduce the [B] quantity a little by redissolving only part of what you took out. Then you can seed the solution again.

Potassium Chromium Sulphate Dodecahydrate

(Chromium Alum – purple, cubic system)

Require: Potassium Chromium Sulphate

Like ordinary alum, chrome alum grows well, but a saturated solution is so dark that you cannot see what is going on. Growing ‘mixed crystals’ of ordinary alum and chrome alum is more satisfactory. Make a solution of chrome alum using 100g of water. Pour this solution into a growing solution of ordinary alum slowly, while you hold the solution up to a light. You can mix the two in any quantities you like, but for convenience stop adding the chrome alum while you can still see through the solution. Notice that the chrome alum solution is a dark blue-green, but the crystals are purple. For the same reason that these mixed alum crystals will grow you can grow one alum over another. For example instead of harvesting a mised alum crystal, you can lift it out-thread and all-and use it as a large seed on which to obtain a further growth of ordinary alum. The final result will be a clear crystal with a lavender crystal inside it. Over a long time, you can grow a very large crystal of any of these alums by the evaporation method. Be sure that the top of the cobra is well under the water surface. Evaporation should be slow, and the crystal should be inspected every few days. If the batch of solution is large enough you can grow the crystal for several months.

Potassium Sodium Tartrate Tetrahydrate

(Rochelle Salt – Colourless, orthorhombic system)

Require: Potassium Sodium Tartrate,

Copper Acetate, Sodium Hydroxide.

Next to alum, Rochelle Salt is the substance best suited for an initial attempt at crystal growing. In growing Rochelle Salt, the seed solution often supersaturates without depositing any seeds. Should no seed appear within two days, add a very few Rochelle Salt particles from the supply bottle. Once started, the seeds will probably grow very quickly and therefore you should inspect them twice a day. The fact that the solubility of Rochelle Salt varies greatly with temperature leads to another problem you may meet. You must be especially careful to observe and control the temperatures at which you work; it is easy to lose the planted seed by dissolving it off the thread before the solution becomes supersaturated. Because the seed and the final crystal dehydrate easily, it is best to keep them in a closed jar, wrapped in a scrap of cloth or cotton batting. Moistening the packing with a drop of the Rochelle Salt solution will furnish added protection. Oddly enough, two different modifications of shape are obtainable by adding copper ions to the growing solution. Five cubic centimeters of a saturated solution of Copper Acetate (one gram of copper acetate in 10cc of water) added to a growing solution of Rochelle Salt made from 100cc of water. You will get long, thin crystals. That last solution with one pellet of Sodium Hydroxide dissolved in it, will grow flat, whole crystals.

Sodium Bromate

(Colourless Cubic system)

Require: Sodium Bromate.

Sodium Bromate crystals tend to develop veils during growth, unless they are grown quite slowly. Moreover, some debris usually forms on the bottom of the jar. The crystals have a tetrahedral shape.

Sodium Chlorate

(Colourless, Cubic system)

Require: Sodium Chlorate, Borax

.Sodium Chlorate crystals grow easily in the form of cubes. A crystal of Sodium Chlorate has the same arrangement of atoms as a crystal of Sodium Bromate, but chlorate ions replacing the bromate ions. The fact that Sodium Bromate grows in tetrahedra and Sodium Chlorate grows in cubes shows that small differences in atomic character can make large differences in crystal growth. You can change the growth shape of Sodium Chlorate by adding some Borax to the solution. The Borax does not becomes part of the crystal, it merely makes the tetrahedral faces appear on the crystal. In order to supress the cube faces completely you must add 6g of borax for every 100g of Sodium Chlorate in the growing solution. You can seed a Sodium Chlorate solution containing borax with a cubical seed of Sodium Chlorate, and see the seed grow into a tetrahedron. Conversely, tetrahedral seeds of Sodium Chlorate grown grown from a solution containing borax will grow into cubes in a pure solution of Sodium Chlorate.

Sodium Nitrate

(Niter and Saltpeter are confusingly used for both Sodium Nitrate & Potassium Nitrate)

(Colourless, hexagonal system)

   Require: Sodium Nitrate

Sodium Nitrate is not as easy to grow as the substances previously mentioned; but it forms a very interesting crystal, sharing many properties with the mineral Calcite and useful in the studies of cleavage, glide, and double refraction. The range of supersaturation within which it grows, well is very narrow and the growth is therefore quite sensitive to temperature change. Seed it first at your usual seeding temperature. Should the seed dissolve, reseed the solution at a slightly lower temperature. If the solution deposits too many unwanted seeds during the growth of the crystal, lower the quantity of the recipie by weighing the crystal and debris and redissolving only part of the total. At best the top part of the crystal will contain veils, but you will be able to cleave them off the harvested crystal.

Potassium Ferricyanide

(Also known as "Red Prussiate of Potash" . This recipe gives red monoclinic crystals.)

Require: Potassium Ferricyanide

.Dissolve 93 grams of potassium ferricyanide in 200ml of warm water, cover the solution, and allow it to cool. Do not be especially afraid of the word "cyanide" in the name; this substance is no more poisonous (and no less!) than the others in the list.

Copper Acetate Monohydrate

 (This recipe gives blue-green monoclinic crystals.)

Require: Copper Acetate, Acetic Acid

Dissolve 20 grams of copper acetate monohydrate in 200ml of hot water. If a scum of undissolved material persists, add a few drops of acetic acid and stir well. Cover this solution, and allow it to cool and stand for a few days; usually it will deposit crystals spontaneously. You can grow large crystals by using them as seeds in the general procedure, but you will find it hard to grow them as large as you can grow the other crystals.

Strontium Formate Dihydrate

(Colourless, orthorhombic system)

Require: Strontium Carbonate, Formic Acid

To 150cc of water, add 18.5cc of 88% formic acid, warm the solution, and add to it 29.5g of Strontium Carbonate, in small portions so that the foaming not excessive. When all the carbonate has dissolved and bubbles of carbon dioxide no longer form in the solution, allow it to cool and deposit crystals.

Lithium Trisodium Chromate Hexahydrate

   (Yello, hexagonal system)

Require: Sodium Dichromate dihydrate,

Lithium Carbonate, Sodium Hydroxide

Dissolve 40g of Sodium Dichromate dihydrate in 130cc of water, and add 7.5g of Lithium Carbonate in small portions. When the bubbling of carbon dioxide has stopped, add 8g of Sodium Hydroxide and stir until it has dissolved. Cover the solution and let it cool and stand. If it fails to deposit crystals spontaneously within a day, add seeds obtained by evaporating a drop of it. Notice that, like alum, this substance is a double compound.

Calcium Copper Acetate Hexahydrate

 (This recipe gives blue, tetragonal crystals.)

Require: Calcium Oxide powder, Glacial Acetic Acid

Add 22.5 grams of powdered calcium oxide to 200ml of water, pour into the mixture 48 grams of glacial acetic acid, and stir until the solution is clear. If there is a small insoluble residue, filter the solution. Dissolve separately 20 grams of copper acetate monohydrate in 150ml of hot water. Mix the two solutions, cover the mixture, allow it to cool for a day. If it does not deposit crystals spontaneously let a drop of the solution evaporate and scrape the resulting seeds into the bulk of the solution. Notice that this solution contains 4 atoms of calcium for every atom of copper, whereas the crystals contain equal numbers of calcium and copper atoms. A solution containing the latter proportion deposits crystals of copper acetate monohydrate, not crystals of the double compound from pure water. But, of course, you can replenish a solution from which you have grown crystals of the double compound by redissolving an equal weight of the compound.