The Rock Cycle

by Heather Krieger


The Rock Cycle
Life of Quin Quartz
Hi! My name is Quin and I belong to the Quartz family. I am a mineral, which means that I am a naturally occurring, inorganic material. I live on Mauna Kea Beach, Hawaii. Right now I'm just a tiny grain of sand, but I used to be much larger.

In fact I've changed many times in the past million years, and I will change again in the future. I'm stuck in a perpetual series of changes called the Rock Cycle.
I began my life as magma, molten rock deep under the ocean in Earth's mantle. When a plume formed, I moved up through the Earth's crust. Over the next 100,000 years, I started to cool and harden. Because I cooled slowly, I was able to grow large crystals and mature into an igneous rock called Granite. Sometimes my friends called me intrusive. I was a part of the massive volcano called Kilauea.
Around 200,000 years ago, the activity inside the volcano was becoming more frequent and extreme. As magma began to rise, I was badly burned through the contact of intense heat. I changed into a metamorphic rock called quartzite. My body pieces were smushed together and I gained at least 500 grams over the next several years.
I spent the next half million years minding my own business as I cycled between molten and solid rock. Out of nowhere, Kilauea experienced a major eruption. I was pushed out of the volcano in a terrifying explosion. As soon as I reached the air, the temperature dropped at least 1,000 degrees. I felt relieved once I became lava! As I was flying through the air, I could already feel myself changing again. I was cooling so quickly that there wasn't time for crystals to form. For the first time, I felt smooth like glass. I was the extrusive igneous rock called Obsidian.
The next 100,000 years or so were great. I was living the good life on beautiful Wailea Beach enjoying the sunshine. I was happy, but after a while I could feel my body aging and changing once again. My smooth surface started to get rough and I suffered some concoidial fractures. I was falling apart. Before too long, I was nothing but a few small grains drifting out to sea.

At first the water was refreshing, but after I settled to the bottom of the ocean, things got worse. Other particles of silt and sand started piling up on top of me. I was becoming more dense and compact and a sticky glue was cementing me to the other particles. I had become sandstone, a sedimentary rock!