This multicolored lily pad is actually a bloom of the iron-based mineral hematite in Brazilian quartz. Danny Sanchez Opal seems to create a burst of blue flame in this Mexican rhyolite. Danny Sanchez ...

Alice Leung picks up a blue sapphire with a pair of tweezers and holds it under a micro­scope, the enhanced image popping up on a computer screen next to her. “See those marks in the corner, the ones ...