South Australia Crystal Growing Competition  

This section is intended to provide information to students and parents, and to teachers involved in crystal growing for fun or for competitions such as the Oliphant Science Awards in South Australia or other crystal growing competitions in other Australian states or indeed overseas.

The majority of competitions require the crystal material to be potassium aluminium sulphate i.e. potash (common) alum. No other material is acceptable for prize consideration.

Students are expected to carry out all manipulations of the material with parent or teacher help where there is a safety issue e.g. hot water. The operations may be carried out at home or at school according to the supervising teacher’s discretion.  To ensure the crystal growing is the student’s own work, the required log book should be checked periodically and some questions asked about the most recent activity.

Other rules which apply to the competition that a participant wishes to enter should be located and read on the appropriate website – for example, the rules for the Oliphant crystal growing competition should be checked on the Oliphant Science Awards website (

Packaging the finished crystal for the competition is important. The finished dry crystal should be placed in small airtight ziplock bag and placed in a Post Pak for posting. The accompanying logbook can be placed carefully folded into the Post Pak or sent separately. [Any crystals wrapped using sticky tape will not be judged]


Judging of the presented crystals is conducted by experienced members of the RACI Chemical Education Group in any state.
Crystals will be judged on the following criteria:

  • regularity i.e. sharpness of edges,
  • smoothness of faces 
  • clarity - overall aesthetic appeal

Size is no longer a major criterion. This will reduce disadvantage to students, who for one reason or another, have less growing time. However, crystals whose largest dimension is less than 9 mm will not be considered for certificates of merit.

Where very similar crystals are difficult to rank for prizes or certificates then the logbooks and the hypotheses proposed will be considered to make a decision. The logbook should state dates from the start to the finish of the growing period and each entry dated and countersigned where possible.

Over recent years the best crystals grown have been smaller and clear with flat, light-reflecting faces and sharp edges, usually suspended from a thread to achieve symmetrical growth.

This link takes you to the rubric used for judging the SA crystals -  (page 11)

Closing dates for final entries to be delivered and judging are determined by SASTA.

Resources for schools are below:

Teacher Notes
Advice To Students
Log Book Model
Material Safety Data Sheet
Hints From Canada
Alum Crystals (David Katz)
ScienceNet CrystalGrowing
Various Views Of AlumCrystals