Rock and Mineral Facts

A rock is a naturally occurring solid. It is made of minerals (which are crystalline), or other mineral-like substances. The minerals in the rocks vary, making different kinds of rock. See the fact file below for more information about rocks and minerals.
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  • All rocks are made of two or more minerals, but minerals are not made of rocks. A mineral is the same all the way through.
  • There are about 3,000 known minerals on the Earth.
  • Quartz is one of the most common minerals found on Earth, and basalt is the most common rock.
  • Diamond is the hardest natural substance on Earth, and a diamond is used to cut another diamond.
  • Marble forms from metamorphosed carbonate rock, most usually limestone.
  • Breccia is a rock composed of generally large, sharp fragments cemented together.
  • The biggest pure-gold nugget was found in Australia in 1869 and weighed 156 pounds. Gold is extremely soft and one of the most valuable minerals.
  • Geodes are plain balls of igneous or sedimentary rock on the outside, but contain beautiful crystals on the inside.
  • Feldspar is a term used for a very large group of minerals which are extremely abundant on Earth. Feldspars make up more than half of the Earth’s crust.
  • The first recorded use of turquoise dates back to 5000 BC in Mesopotamia, where people used the gemstone to make beads, and lapis lazul is treasured for its rich blue color and is often used in jewelry. The ancient Egyptians used powdered lapis lazul as eye shadow. Jade is extremely strong which made it a perfect choice for making things like fish hooks, knives, hammers and axes throughout history.