Rocks

Rocks are interesting

Diamond

If you look at the chemistry of diamond, it is pure carbon. The different arrangement of the carbon atoms makes it a unique gem. Diamonds have been considered precious since ancient times and is popular for their strength, hardness and purity. But only in the hands of a master diamond cutter does a diamond's sheer beauty become apparent.


Diamonds were formed in the earth thousands of years ago under extreme heat and pressure. This extreme heat and pressure in the earth transformed the carbon into crystals and turned it colorless. Although diamonds formed deep in the earth, volcanic activity is what brought them to the surface. Hence, these volcanic pipes have diamonds in them. Over time, as some other minerals mix with carbon the diamond may takes on color. Most diamonds have some hint of yellow or brown in them. Others that did not mix with minerals are colorless. Some diamonds undergo dramatic changes to vivid or unique colors. These are very rare and valued more than normal diamonds.

The Secret Life of Rocks - a Documentary

Sedimentary Rocks

The earth's surface is constantly being eroded. This means that rocks are broken up into smaller pieces by weathering agents such as wind, water, and ice. These small pieces of rock turn into pebbles, gravel, sand, and clay. They tumble down rivers and streams. These pieces settle in a new place and begin to pile up and the sediments form flat layers. Over a long period of time, the pieces become pressed together and form solid rock called sedimentary rock. Most sedimentary rocks form under water. Most of the earth has been covered by water some time in the past. 70% of the earth is covered by water now. So sedimentary rocks are common all over the world. Sedimentary rocks are often rich in fossils.


Sedimentary rocks are used for:

  • Coal is burned to create energy.
  • Gypsum is used to make plaster of Paris and in drywall and board chalk
  • Sandstone and limestone are used as building stone and in the production of glass.
  • Limestone is also used for hard core in roads, and is cooked to make cement.
  • Shale is mixed with sand and used to make bricks.
  • Iron ores are mined and smelted to create iron metal.
  • Smectite clay is used as a digestive cure.
  • Salt is an essential food.
  • Scientific research

Metamorphic Rocks

Metamorphic rocks are rocks that have "morphed" into another kind of rock. These rocks were once igneous or sedimentary rocks. How do sedimentary and igneous rocks change? The rocks are under tons and tons of pressure, which fosters heat build up, and this causes them to change. If you exam metamorphic rock samples closely, you'll discover how flattened some of the grains in the rock are.

Igneous Rocks

Igneous rocks are called fire rocks, and are formed either underground or above ground. Underground, they are formed when the melted rock, called magma, deep within the earth becomes trapped in small pockets. As these pockets of magma cool slowly underground, the magma becomes igneous rocks.

Igneous rocks are also formed when volcanoes erupt, helping the magma to rise above the earth's surface. When magma appears above the earth, it is called lava. Igneous rocks form as the lava cools above ground.

Obsidian

Obsidian rocks are igneous rocks that form when lava cools quickly above ground. Obsidian is actually glass and not a mixture of minerals. The edges of this rock are very sharp.