Young Lava and Old Olivine
June 25, 2020
Photographer: Mila Zinkova
Summary Author: Mila Zinkova
Have you ever held a rock that was created an hour ago? I did (top photo) in July of 2018. This rock was created when debris from a steam explosion hit a boat touring newly-formed lava on the Big Island of Hawaii. The explosion produced hot rocks (lava bombs) that landed on the boat and actually injured several tourists. Because my hotel was nearby, I noticed that the boat came back 2-hours before it should have, so I went to the pier to see why. Click here to see what I saw. Two days before, I took the same tour with the same company.
While the rock from the first picture is the newest I've ever held, the rock pictured in the bottom photo is one of the oldest. It is a meteorite, a pallasite to be exact. If you look closely you’ll notice it has some greenish-yellowish crystals. These are olivine crystals. Pallasites are stony-iron meteorites that contain olivine and iron. They’re believed to come from the core of large asteroids. Olivine is usually green, but it often doesn’t last long in meteorites. It turns out that Earth’s atmosphere isn’t a healthy environment for pallasites since they’re prone to a type of chemical weathering referred to as Lawrencite disease, which causes olivine to be removed.
The lava rock in the first photo has olivine too -- olivine often occurs in lava rocks. In fact, a green, sand beach on the Big Island of Hawaii formed when olivine-rich lava eroded as it reached the ocean.
Photo Details: Top - Camera: Apple iPhone 8; Software: Adobe Photoshop CS3 Windows; Exposure Time: 0.0039s (1/257); Aperture: ƒ/1.8; ISO equivalent: 20; Focal Length (35mm): 139. Bottom - Camera: Apple iPhone 6; Software: Adobe Photoshop CS3 Windows; Exposure Time: 0.0016s (1/608); Aperture: ƒ/2.2; ISO equivalent: 32; Focal Length (35mm): 76.