Arsenopyrite with Calcite and Quartz
Arsenopyrite
– FeAsS
Orthoclase
Talc (1)Diamond (10)
Scratches glass. Harder than a steel knife.
Calcite
– Ca(CO3)
Calcite
Talc (1)Diamond (10)
A copper coin can scratch it.
Did you know?
Geologists long knew arsenopyrite by a striking test: a sharp knock throws sparks and releases a distinct smell of garlic.
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.
Pressing a quartz crystal makes it give off a precise electric beat, which is why it keeps time in nearly every watch and once tuned the radios of World War II, when good crystals were a strategic resource.
