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How Jade Forms

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George Harlow

Jadeite is like a time capsule. It holds important clues about some of Earth's big events, like earthquakes, mountain building, and plate collisions.

Deep in the Earth

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scrapbook page with pictures explaining subduction, and steps to how jade forms
picking through stones on the surface to find jade

Jade in the field

Imagination is key for geologists. Jadeite forms deep inside Earth. I can't go there or see how it forms. Ao I try to imagine what Earth is like deep inside based on the pieces of jade that I find on the surface of Earth. I'm still trying to figure out exactly how jade forms.

illustration showing one tectonic plate sinking under another

subduction

When one tectonic plate subducts, or sinks under another, rocks and water are pushed into Earth's mantle.

jade with many colors and patterns in it

clues to Earth

Take a closer look at this piece of jade. See its patterns and changes in colors? Each layer is like a record of what went on deep inside Earth long ago! They hold important clues about how plates collide. And they help us understand dynamic Earth processes.

illustration of small crack through earth

1. Earthquakes form small cracks

As the plates press against each other, earthquakes occur. The rocks that are rubbing against each other break and shatter, forming small cracks. Water is squeezed out of the rock under the high pressures deep inside Earth.

illustration of green jade forming in crack in earth

2. Jade forms

The escaping water rises along the cracks in the rocks. The water is full of dissolved minerals. As it flows through the cracks, it leaves jade behind, causing the cracks to get clogged.

more layers of jade in many colors deposit in crack in the earth

3. More layers of Jade form!

When another shift or earthquake occurs, the old crack or a new one opens. More water with dissolved jade passes through the cracks and a new layer of jade is formed. This process repeats over and over again. For large jade deposits to form, it must take millions of earthquakes!

Image Credits:

Field and raw jade photos: courtesy of George Harlow and colleagues