Rock

TYPES OF ROCK

Rock is the constituent of the Earth's crust, either in its unconsolidated form as clay, mud, or sand, or consolidated into a hard mass as igneous rock, sedimentary rock, or metamorphic rocks. (Consolidation is the process which turns the matter into a more or less hard substance.)

Sedimentary rocks are the most common rocks on Earth. They form at or near the Earth's surface.

The approximate amounts of different kinds of sedimentary rock are;
Shale (including mudstone, and siltstone): 60%
Sandstones 20%.
Carbonate rocks (limestone and dolomite): 15%.
All others: 5%.

Bedford shale

Trovants are a type of rock in Romania that can grow and multiply.

Basalt is the most common type of rock on Earth.

More than 90 percent of all volcanic rock on Earth is basalt

California is home to a wider variety of rock types than any other U.S. state.

FUN ROCK FACTS

Petrology is the scientific study of rocks.

The poet Samuel Taylor Coleridge invented the sport of rock-climbing. On August 5, 1802, Coleridge set off on a tough 9-day walking and climbing tour of the Lake District, which would include Scafell, the second highest peak in England.  Coleridge made the first recorded ascent of Scafell and his descent via the rockface of Broad Stand is hailed as the first ever recreational rock climb.

Mount Augustus in the Australian Outback is the largest rock on Earth. It can be seen from almost 100 miles away and is about 2,352 feet high.

Moiunt Augustus. By Graeme Churchard from Bristol, UK 

The volcanic rock known as pumice is the only rock that can float in water.

When a rock is dropped into water, an hourglass-shaped cavity of air is created, which ejects the air faster than the speed of sound.

The Kailasa temple in India was carved out of a single rock. Also known as 'Cave 16' of the Ellora Caves, the Hindu temple is notable for being the largest monolithic structure in the world carved out of a single piece of rock.

Kailasa Temple, Ellora by Pratheepps 

PET ROCK

In 1975 advertising executive Gary Dahl came up with the idea of pet rocks. The theory was that they a rock would be a perfect pet as it did not need to be fed, walked, bathed, or groomed, and would not die.

Pet rocks were marketed like live pets in custom cardboard boxes. Inside was the instruction manual and a smooth Mexican beach stone on a bed of straw.

Pet Rocks sitting on a couch. By Owner of Pet Rock Net 

Dahl sold 1.5 million Pet Rocks for $4 each, and became a millionaire.