If Hawaii’s Kīlauea volcano were to offer an apology for its chaos and destruction, it just might come in the form of a beautiful green mineral called olivine.
Over the past months we’ve reported on devastating lava flows and bone-shattering boulders. Now it’s raining gems – a rare event that has geologists enthralled and the rest of us just plain confused.
Before you go racing off to Hawaii with dreams of making it rich, you should know a bit about the science behind this amazing event.
Olivine is an incredibly common mineral – chemically speaking, it’s magnesium iron silicate. Carried to the surface on volcanic hotspots, it often taints dark igneous rocks such as basalt with mossy green hues.
Finding it in the form of discrete lumps that jewellers would recognise as a gem called peridot is surprisingly rare – thanks in part to its tendency to weather into tiny sand-grains quite quickly.
Right now, Hawaii’s residents are having no such trouble. Decent-sized crystals have been found amid the rocks and ash of recent eruptions and a’a lava flows.
Friends of mine live in Hawaii, right next to the area impacted by the most recent lava flows. In the midst of the destruction nearby & stress of the unknown, they woke up to this – tiny pieces of olivine all over the ground. It is literally raining gems. Nature is truly amazing. pic.twitter.com/inJWxOp66t
— Erin Jordan (@ErinJordan_WX) June 11, 2018
Some olivines that popped out of an a’a flow. Kilauea’s little gems. #hawaii #kilauea #olivine #lovevolcanoes https://t.co/1X2ACcWu7n pic.twitter.com/8UaA1IrKEd
— GEOetc (@GEOetc2) June 10, 2018
It seems that the violence of recent eruptions has sprayed magma high into the air, where the high crystallisation temperatures of magnesium iron silicates has allowed them to quickly transform into olivine stones before they hit the ground.
Up goes hot molten rock, and down comes a rain of peridot.
Collecting buckets of these lovely green pebbles probably won’t increase your bank balance a great deal. It’s not exactly an expensive gem.
But they’re certainly pretty – and at least it’s something nice coming out of the recent destructive streak of Hawaii’s formidable volcano.