Sand & Gravel Quarry
Rocks
Earth materials are naturally formed materials found beneath the surface of the earth. These materials can be grouped as:
- Liquids (water, oil, mercury, magma)
- Gases (methane and other gases found, for instance, beneath the North Sea, and gases such as CO2 and SO2 found in volcanoes)
- Solids (rocks, sediment, soil)
Rocks are part of the third group, solids.
There are hundreds of different types of rock. Most people think of all rocks as being very hard and perhaps big as well. But softer, smaller materials such as sand, gravel, clay and peat are also rocks.
OK, most rocks are hard and stiff, but some are bendy. There’s even an unusual type of Indian sandstone that can be bent by hand.
Limestone is a fairly hard rock made from calcium carbonate
Granite is a very hard rock
Sandstone is a soft rock – you can scratch it with your nails
Chalk is a soft rock made from calcium carbonate – you can easily rub bits off
Marble is a rock made from calcium carbonate crystals – you can smooth and polish it
Slate is a hard rock made of layers – it splits easily into sheets