Alum Crystal

back to Crystal Growing...

[[File:

Grocery store alum

][1]]] [[File:

Alum crystal

][2]]]

Alum Background

From the wikipedia page on Alum

You may find it in the grocery store's spice aisle. It is often used to make pickles crispy, but can also be used to grow large, diamond like crystals. Alum is a hydrated double sulfate salt of aluminum and potassium. “Alum” also known as aluminum potassium sulfate.

Alum is a non-toxic compound, with medicinal uses, but may cause eye irritation.

What are Crystals?

Crystals may be found in nature or created in a lab and are characterized as having an orderly, repetitive atomic arrangement. This arrangement is known as a crystal lattice. Large single crystals are identifiable by their geometric shape, often including flat faces. Many inorganic solids are polycrystals, rather than crystals. A polycrystal is a fusion of many individual crystals into one structure. Recrystallization is a common technique used to purify substances.

Creating Alum Crystals

Alum is a small white crystal. A larger alum crystal structure can be created from the compound. General steps are listed below:

1. Pour hot water into a clean container
2. Slowly add alum, until saturated solution is created. Food coloring can be added at this stage.
3. Lightly cover saturated alum solution with paper towel to avoid contamination
4. 12-24 hours later, transfer solution to new container, at the bottom of this container are the “seed crystals” used to grow a larger crystal
5. Tie string around the largest “seed crystal”
6. Let the “seed crystal” hang in the saturated alum solution, without touching the bottom or sides of the container
7. Add more alum to the solution to maintain a saturated solution

Examples

Video"DIY Crystal at Home"[3]

Video"Grow Transparent Single Alum Crystals"[4]

Protocol "Growing Alum Crystals"[5]