IN THE CLASSROOM:Not just a bag of rocks to these kids

Jose Chamu thought his backpack felt heavy all of a sudden.

The Davis Elementary School fourth-grader was camping with his family over winter break when he left his bag open on a hillside for a few hours. When he slung it back over his shoulders, he could tell that something wasn’t right.

Inside the backpack were several rocks, which Jose guessed had rolled down the mountainside and landed in his pouch.

He promptly shook them out, but then he came to one that made him pause: pink and orange, oval-shaped, full of tiny holes and splashes of color.

“I found it, and it was so beautiful, I dropped all the other ones in the lake,” said Jose, 10, of Costa Mesa.

On Thursday, the rock became a part of Davis Elementary’s permanent science collection.

Jose’s class had been studying rocks during its weekly science lessons since October, and the latest discovery proved once again how different rocks can be.

“Doesn’t that rock look like chopped meat with a lot of fat in it?” science teacher Pam Brusic told the class as Jose showed his treasure on the overhead projector.

There are indeed all kinds of rocks in the world — and they develop in all kinds of ways.

On Thursday, the last day of the class’ rock unit, Brusic provided the students with egg cartons full of rocks and asked them to figure out which ones fit in which category: igneous (created from magma), sedimentary (compacted out of loose material) or metamorphic (forged through heat and pressure).

Learning about rocks in Brusic’s class can have rewards beyond a good grade.

At the front of the room, the teacher kept 10 rocks of different shapes and colors — shiny and pink, sleek and black, brown and lumpy — and invited students to drop slips of paper in a jar guessing the type of each one. A correct guess meant a “Caught in the Act” slip, which the school draws every Friday to award prizes to students.

Arshdeep Kaur, 9, said learning about rocks gave her ideas for making necklaces in her weekly jewelry class at Davis.

Leo Doan, 9, said he had developed a better eye after learning the different types of stones.

“My favorite rock is obsidian,” he said. “It looks shiny, and you can probably find it in California.”