Crystals

General Information

Potassium alum is one of the possible combinations of alum. There is also chrome alum and ammonium alum.[1]

Production Methods

Potassium alum crystals are very clear when they are grown slowely. This easiest way to do this is by evaporating a saturated solution. Cooling down a supersaturated solution has to be done slowely (using proper isolation) to prevent the crystals from become slightly opaque. Chrome alum can be combined with potassium alum to make light purple crystals. It's also possible to make a crystal that gets gradually lighter from the center outward by using a solution with an increasing amount of potassium alum dissolved in it.[1]

Chemical & Physical Information

For more information, also look at the potassium alum chemicals.

Photos

(3 cm)

Sources

[1] Wikipedia

[2] Specimen from my personal collection, photo taken by me.