ROCKS ARE BURIED TREASURE-They are full of valuable minerals and contain metals, gemstones,fossils and even fuels like coal and petroleum.Every type of rock contains different minerals.There are about 4,000 minerals found on Earth.They have their own unique shape and color.
Broadly rocks are of three types-
Igneous &nbs p; rocks- These are&nbs p; formed when molten lava comes out of a volcano. When it cools , it crystallizes into solid rock.
Sedimentary Rocks- These are made from loose rocks and ancient remains of animals and plants carried by wind and water,they compact and hardened into solid rock over millions of years.Most fossils are found in sedimentary rocks.
Metamorphic rocks These rocks are formed when Igneous and sedimentary rocks come under heat and pressure.Then these rocks change their shapes to form metamorphic rock.
Like ,under pressure and heat lime stone changes into marble,Clay changes into slate.
Our Earth also made out of molten rock.But about 4 billion years ago ,the outer layer began to cool and form a hard crust.
CRYSTAL-
Crystals are minerals that grow into regular shapes with smooth ,flat faces and sharp edges
A crystal's shape is known as its habit.Salt crystals are like tiny cubes, Zircon crystals ,used in jewellery are like pyramids, while asbestos grow in long strands.
Millions of tiny crystals can cluster together to make a chunk of rock.
Crystals can grow underground to an incredible length of 11 m(36ft).
GEMS- The size of a gem is given by weight units called Carats.One carat is the same as 200 mg(0.007 oz)
The most valuable gem is Diamond.
SOME FAMOUS DIAMONDS IN THE WORLD-
REGENT-(140.5carats),It was found in 1698.It was later stolen by an English sea captain.In 1812 it was used to decorate Napoleon's sword.
KOH-i-NOOR-(105.6 carats)Since 1304, it was belonged to various Indian and Persian rulers, but became a part of the British crown jewels after Queen Victoria became Empress of India in 1877.
BLUE HOPE.(45.5 Carats) One of the famous owner of this diamond was Marie Antoinette, wife of king Louis XVI of France.The curse was that she was beheaded in 1793, during the French Revolution .
STAR OF AFRICA-(530.2 carats) In 1908 this diamond was mounted in the royal Scepter, part of the British crown jewels
MILLENNIUM STAR-(203 carats)- It was discovered in 1990, it took three years for lasers to cut and shape this pear shaped diamond.
SOME FAMOUS ROCKS-
MOUNT RUSHMORE- Four American presidents face were carved out of a rock in South Dakota.
SHIP ROCK- The ship rock in New Mexico, USA is a giant pillar of stone that rises 500m (1,640ft) out of the plain.
DELICATE ARCH- This is 16 m(53ft) high sand stone arch has worn away over time by weathering and erosion.
ULURU- In central Australia lies one of the world's largest single piece of rock 383 m(1,256ft) high and 2 km (1.2 mile) long.
SUGAR LOAF MOUNTAIN-his majestic mountain is in Rio de Jeneiro, Brazil, rises to 396 m(1299ft).
INTERESTING FACTS-
Broadly rocks are of three types-
Igneous &nbs p; rocks- These are&nbs p; formed when molten lava comes out of a volcano. When it cools , it crystallizes into solid rock.
Sedimentary Rocks- These are made from loose rocks and ancient remains of animals and plants carried by wind and water,they compact and hardened into solid rock over millions of years.Most fossils are found in sedimentary rocks.
Metamorphic rocks These rocks are formed when Igneous and sedimentary rocks come under heat and pressure.Then these rocks change their shapes to form metamorphic rock.
Like ,under pressure and heat lime stone changes into marble,Clay changes into slate.
Our Earth also made out of molten rock.But about 4 billion years ago ,the outer layer began to cool and form a hard crust.
CRYSTAL-
Crystals are minerals that grow into regular shapes with smooth ,flat faces and sharp edges
A crystal's shape is known as its habit.Salt crystals are like tiny cubes, Zircon crystals ,used in jewellery are like pyramids, while asbestos grow in long strands.
Millions of tiny crystals can cluster together to make a chunk of rock.
Crystals can grow underground to an incredible length of 11 m(36ft).
GEMS- The size of a gem is given by weight units called Carats.One carat is the same as 200 mg(0.007 oz)
The most valuable gem is Diamond.
SOME FAMOUS DIAMONDS IN THE WORLD-
REGENT-(140.5carats),It was found in 1698.It was later stolen by an English sea captain.In 1812 it was used to decorate Napoleon's sword.
KOH-i-NOOR-(105.6 carats)Since 1304, it was belonged to various Indian and Persian rulers, but became a part of the British crown jewels after Queen Victoria became Empress of India in 1877.
BLUE HOPE.(45.5 Carats) One of the famous owner of this diamond was Marie Antoinette, wife of king Louis XVI of France.The curse was that she was beheaded in 1793, during the French Revolution .
STAR OF AFRICA-(530.2 carats) In 1908 this diamond was mounted in the royal Scepter, part of the British crown jewels
MILLENNIUM STAR-(203 carats)- It was discovered in 1990, it took three years for lasers to cut and shape this pear shaped diamond.
SOME FAMOUS ROCKS-
MOUNT RUSHMORE- Four American presidents face were carved out of a rock in South Dakota.
SHIP ROCK- The ship rock in New Mexico, USA is a giant pillar of stone that rises 500m (1,640ft) out of the plain.
DELICATE ARCH- This is 16 m(53ft) high sand stone arch has worn away over time by weathering and erosion.
ULURU- In central Australia lies one of the world's largest single piece of rock 383 m(1,256ft) high and 2 km (1.2 mile) long.
SUGAR LOAF MOUNTAIN-his majestic mountain is in Rio de Jeneiro, Brazil, rises to 396 m(1299ft).
INTERESTING FACTS-
- Although both Diamond and Graphite, form of carbon, graphite is dark grey ,and one of the softest minerals, while diamond is clear and the world's hardest natural substance.
- Some minerals like magnetite are naturally magnetic.
- Uraninite is a radioactive mineral from which Uranium is extracted.
- Some minerals such as Soda lite grow,when ultraviolet light is shown over them.
- About 100,000 tonnes of Uranium ore produces 25 tonnes of radioactive uranium, the annual amount ,used by a nuclear power station.
- Mineral ID ,to identify a mineral one has to test for its various features.like-
- Color ,luster, and habit-color of mineral's crystal, its shine(luster), and the form(habit) of its crystals.
- Streak-,the color of streak left by the mineral when rubbed across a tile.
- Cleavage- how the mineral break when hit with a hammer.
- Hardness- It is measured on the mohs scale from 1(very soft) to 10( hard)
- Crystal system- The basic geometrical shape of mineral's crystal.
- IGNEOUS ROCKS-
SEDIMENTARY ROCKS-
METAMORPHIC ROCKS
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