Bumblebee Jasper, a Volcanic Gemstone (Patreon)

The cabochon shown above was cut from a beautiful material known as "bumblebee jasper". Despite its name, it is not truly a jasper (SiO2) but instead a hydrothermally altered variety of calcite (CaCO3). The yellow-orange inclusions are realgar, and the black are very tiny crystals of pyrite. Thick beds of this unique gemstone exist underneath the unstable northeast flank of Mount Papandayan in Indonesia, which only became exposed after a catastrophic flank collapse in 1772. This fascinating volcano in Indonesia is a reminder that somewhere on the planet about every 25 years, a large flank collapse occurs, leaving behind a horseshoe shaped caldera.