Welcome to Rocks and Minerals! I’m COAL, and I’ll be your guide around here. Imagine your feet as the home of a crowd of crystal-cool characters, each with their own personality. They’re the underworld beings who are the building blocks of our planet. Click on my friends to the left to meet them.

As the hardest mineral on Earth, I am completely resistant to chemical attacks and never get dulled by scratches and nicks. Showing off my dazzling winsome faces, I also drive the ladies wild.

(or Flinty to my friends). I dress in dark colors of black, gray and deep brown to show that I’m not to be messed with, and when stuck, I make sparks fly.

Like the blood in your veins, I’m a rich source of iron. I have a wide range of costumes, but my most recognizable form is smooth, rounded kidneys—I kidney you not!

a milky green mineral. My toughness makes me ideal for carving, and I was revered in Asian society, where I was thought to hold cosmic energy.

Hello, gorgeous! I’m MARBLE.
Waxy and clear, my flawless complexion drives artists and architects wild. I was a favorite for triumphal buildings during the Roman Empire.

—a light, frothy fellow who’s proud to be the only rock that floats. Full of holes, I am 90 percent cavities with smooth walls.

an abrasive character. Because my grains form sand, people see me as a beach bum with a sunny disposition. The secret of my success is my durability.