Opal layers in an outcrop located in Valles Marineris as imaged by HiRISE. HiRISE ID: ESP_022620_1690   Image credit: ASU/NASA

Opal layers in an outcrop located in Valles Marineris as imaged by HiRISE. HiRISE ID: ESP_022620_1690 Image credit: ASU/NASA

Greetings, Earthlings!

On this segment of Universe Playpen, we’re going to take a fascinating look at opals on Mars!

Now, you have probably heard about opals- the really pretty iridescent mineral usually made into jewelry or found at rock and mineral shows!

Opal is a type of mineral actually called a mineraloid. Mineraloids are where its silica crystal nature is amorphous (not structured). Its also a “hydrated silica”, meaning it has water in its chemical formula, but not entirely water-based (usually between 6-10% water in its structure!)

BUT….

Having a little bit of a water-based mineral on a planet with no present water on the surface is the real mystery! How did the opals form? We do know that there must have been ancient water all over Mars to some extent, but the formation of opals is still even being studied here on Earth!

Finding opal fields on Mars, like from the HiRISE camera, to finding opals under microscopes from martian meteorites- these could be a clue as to the entrapment of water, mineral formations on an early Mars, and maybe even entrapment of ancient bacteria in that water!

 Piece of the Nakhla martian meteorite that was discovered to have microscopic pieces of opal! Image credit: http://www.geologyin.com/2016/09/discovery-of-opal-on-mars-hints-at.html

Piece of the Nakhla martian meteorite that was discovered to have microscopic pieces of opal! Image credit: http://www.geologyin.com/2016/09/discovery-of-opal-on-mars-hints-at.html

Thank you for reading and come back next week for a look at the Rembrandt Crater on Mercury!