Popcorn rock is an amazing mineral. It is a special variety of limestone that is mined in Utah. This limestone contains calcite and other trace minerals. When the limestone is completely submerged in distilled white (only) vinegar, the calcite crystals are released and then regrown as aragonite crystals. The aragonite will harden over time and may be kept indefinitely. Popcorn rock can be regrown by cleaning off the rock completely, waiting until it is completely dry, then put back in distilled white vinegar. Rock may be broken into two or more pieces for more fun (Final result may yield smaller crystals, though.) Popcorn rock can be grown in different colors. After half of the vinegar is gone, dip a toothpick in some food coloring then swirl that very small amount in the remaining vinegar. Too much food coloring will make the crystals too dark. Popcorn rock is an excellent school/home school science experiment. The vinegar is a great example of a catalyst at work. The reaction and result is similar to the way mollusks grow their shell. Clams and Oysters, for example, ingest tiny protein creatures for food and sand. The protein converts to an acid (like vinegar) which helps break down the sand (like calcite.) This liquefied sand reforms as an aragonite shell. This is similar to the aragonite crystals that grow on the Popcorn rock. For best results, place popcorn in container with the highest point up(Think of a pyramid.) A single large cluster will grow off of a point rather than a flat surface. The aragonite grown is very good for removing impurities in it's environment.

All rocks guaranteed to grow!

Crystals form in about 2-3 days.

Can be regrown and economically broken into more pieces.

Excellent time vs. growth, mineral transformation science experiment.

Grow different colors. Purify your envirnonment, naturally.