A “perfect” alum crystal is colorless, clear, and octahedral. It’s the chemical of choice for the annual US Crystal Growing Competition, which University at Buffalo chemistry professor Jason Benedict has organized since 2014. But a few added ingredients open a range of creative possibilities for crystal art made from alum, aka aluminum potassium sulfate dodecahydrate, AlK(SO4)2∙12H2O. Feast your eyes on the winners in this year’s “Coolest Crystal” category, and then head on over to www.uscrystalgrowingcompetition.org/uscgc-winners to see all the winners. The crystal-growing clock starts each year during National Chemistry Week in the fall, and the USCGC website has a wealth of instructions and tips. Start practicing now and maybe you’ll make the leaderboard next year.
Courtesy of Jason Benedict
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