They also extracted and analyzed tiny water droplets trapped within the calcite crystals – essentially fossil raindrops preserved for millions of years – to determine where this ancient rainfall ...

which glowed pink under black light. The calcites grew underground, fed by the manganese-rich water. Sebree believes that when these rocks shattered, since calcite is weaker than the limestone ...

Enter this guide by [Mithuna] from Looking Glass Universe, where she circles back on the concept of measurement basis in quantum mechanics using a rather simple piece of calcite crystal.