Rock Facts
The department has had a special request this week from Mrs Snowdon, who professed her secret love of rocks, and wanted some interesting facts that she can wow her family, friends and colleagues with. Here are a few to get you going Mrs Snowdon…
The oldest rocks on Earth, called zircons, are about 4.4 billion years old. They were discovered in Western Australia and provide a glimpse into our planet’s early days.
Geologists use the Mohs scale, which was set up in 1812 to measure how hard a rock is. The higher the number, the harder the rock. Diamond, the most famous gem and the hardest material on Earth, is a 10 on the Mohs scale.
Certain types of rocks, like gypsum can grow over time. This happens when mineral-saturated water evaporates, leaving behind mineral deposits that accumulate and form rock.
Some rocks float! Pumice, a type of igneous rock, can float on water. This is due to its unique formation process, which involves rapid cooling and depressurization of gas-rich magma, creating a rock filled with air bubbles.
The colours inside some rocks and minerals have been used by artists for thousands of years. For example, the powder of a mineral rock called cinnabar makes a brilliant red colour that was widely used in art in the Middle Ages.
And finally, to link it back to English, there are slightly different words that we often interchange (and use wrongly!) when talking about this subject…
Mineral – A naturally occurring solid compound with an orderly internal structure.
Rock – An exposed section of the Earth’s crust that is made up of minerals.
Stone – A piece of rock.
Mineraloid – Naturally occurring but non-crystalline solid compound, (e.g. obsidian for all you Minecrafters out there).
Mr Bowles
Curriculum Leader for Geography
