Minerals Flashcards
In geology, what is a mineral?
A mineral is an element or compound. It is a naturally occurring solid substance occurring in the Earth’s crust, with its own chemical composition, structure and properties. Minerals are the building blocks of rocks.
Why are coal, oil, and natural gas not minerals?
Coal, oil, and natural gas are NOT minerals because they are not solids.
Name the main physical properties used to identify minerals and briefly explain each one.
Hardness
Lustre
Colour
Streak colour
Explain what is meant by the term ‘lustre’
Lustre is a measure of the gloss or brilliance of reflection of light from a mineral’s surface. In other words, the shininess of a rock’s surface.
Explain the term ‘hardness’ in reference to rocks.
Hardness is a measure of the resistance of a mineral to being scratched.
How is ‘hardness’ measured?
Hardness is assessed by comparing minerals using the Mohs scale.
What is ‘streak colour’?
Streak colour refers to the colour left behind when you try to scratch an unglazed white tile with the mineral.
Name some common minerals.
Talc, feldspar, quartz, diamond.
Which one is true?
1. elements make up minerals, minerals make up rocks
2. minerals make up elements, elements make up rocks
- Elements make up minerals, minerals make up rocks
Why do rocks differ in the way they look and feel?
a. They are made up of different combinations of minerals.
What are minerals made up of?
Minerals are made up of crystals.
What are crystals?
A crystal is a solid substance with its atoms organised in a regular pattern with flat surfaces.
Does the structure of a crystal affect a mineral’s properties? Explain.
Yes, the structure of a crystal influences a mineral’s properties. For example, the minerals called graphite and diamond are both made of pure carbon but they have their atoms arranged differently. Graphite has its atoms arranged in a way that means the mineral is soft. Diamond is one of the hardest minerals on Earth.
Talc has a score of 1 on the Mohs scale. Diamonds have a score of 10. What does this mean?
Talc is soft and diamonds are hard. Talc is the softest mineral and can be easily scratched by all other minerals. Diamonds are very hard.
Why are minerals like diamonds, gold, and silver valuable?
Because they are rare and beautiful.
