Did you know?
Mimetite is named from the Greek for imitator, after how closely it copies pyromorphite. Its cheerful orange and yellow crystals hide a grim makeup, an ore of toxic lead and arsenic.
Look through a clear rhomb of Iceland spar calcite and the world doubles, split into twin images by the crystal's double refraction. Some researchers think Norse sailors used this very effect to find the sun through cloud, the so-called sunstone, though the idea remains a debated hypothesis.