Topic 2 - Rocks - Recycling The Planet Flashcards
What is the diameter of the earth in km?
12 742 km
How thick is the atmosphere around Earth in km?
100 km
How long ago was the earth created?
4.6 billion years ago
What are the 3 types of rock varieties?
Igneous
Metamorphic
Sedimentary
How are igneous rocks formed?
By cooling and solicitation of molten liquid rock
How are metamorphic rocks formed?
By recrystallisation of pre-existing rock as a result of changes in pressure and temperature
How are sedimentary rocks formed?
By the accumulation and burial of layers of rock debris
By lithification of materials that were originally weathered from pre existing rocks
What is the definition of ‘mineral’?
In everyday language it can mean:
Anything that is neither an animal nor a plant
Certain chemical components of food
In earth science it means:
A mineral is a solid material, formed by natural processes, with a chemical composition that falls within certain narrow limits and with its constituents atoms arranged in a specific regular ,three dimensional array or pattern.
Is mineral water a mineral?
Mineral water is not a mineral because it is not solid. It is named this way because the water contains a small amount of dissolved material derived from having been in contact with soluble minerals underground.
How many different minerals are there?
Almost 4000 and new ones are being discovered every year
What is a crystal?
It is a closely related term to mineral, which describes a solid material whose atoms are arranged in a specific, ordered arrangement. This arrangement gives rise to the material having flat faces arranged in a particular orientation and hence he characteristic geometrical shape such as a cube or octahedron.
How can different minerals vary in terms of their composition and or atomic structure and display contrasting physical properties and appearances as a result. How can they be differentiated?
Colour
Lustre
Form or shape
What is the lustre of a mineral?
The appearance caused by how light is reflected from the minerals surface for example, metallic, glassy(or vitreous) or dull
How can the form and shape of a mineral affect a mineral?
Crystal form often mimics atomic structure
Crystals are much longer than they are wide are said to have a prismatic form
Crystals that are flat are said to be tabular
Crystals with square faces intersecting at 90 degrees are cubic
Crystals with six equal sided faces that don’t intersect at 90 degrees are rhombohedral
What other properties can be used to classify and identify minerals other than colour, lustre or form?
Density
Hardness
The pattern on a fractured broken surface
How is density measured in minerals?
Grams per cubic centimetre
Kilograms per cubic metre
What is the hardness of a mineral influenced by?
The atomic structure
What is a conchoidal fracture?
A fracture that looks like concentric bands seen on some shells such as mussels.
Describe what the mineral property ‘cleavage’ is ?
The tendency for a mineral to break apart along preferred planes of natural weakness in its crystal structure.
Why does cleavage of a rock occur?
It is a consequence of the way the constituent atoms are arranged.
Which mineral shows the property cleavage very clearly? And how is it arranged.
Mica
It’s atoms are arranged in layers or sheets , so crystals of mica tend to split apart parallel to the sheets like the pages of a book. Mica has just one set of cleavage surfaces parallel to each other, so this is why mica forms platy or flake like crystals.
What is the chemical composition of amphibole?
Iron Magnesium Calcium Aluminium Silicate containing water
What is the crystal form and colour of amphibole?
Black and elongate
What is the cleavage of amphibole?
2 sets of cleavage
Planes intersecting at about 120 degrees when crystals viewed end on
What is the chemical composition of calcite?
CaCo3
What is he colour of calcite?
White
How many sets of cleavage does calcite have?
3
What does calcite react with and what does it produce?
Acid
It produces Co2 gas
What is the chemical composition of feldspar?
Occurs as two types
Potassium-aluminium-silicate
(Potassium feldspar variety)
Sodium - calcium- aluminium- silicate (plagioclase feldspar variety)
What is the crystal form of feldspar?
Prismatic, tabular
What colour does feldspar appear?
White and pink
What is the chemical composition of Garnet?
Iron Magnesium Calcium Aluminium Silicate
What is the colour of garnet?
Red- brown
What is the crystal form of garnet?
Equidimensional, 12 sided (dodecahedral)
What is the chemical composition of Halite?
NaCl (sodium chloride)
What is the crystal form of halite?
Cubic
What is the colour of Halite?
White
What is the chemical composition of kyanite?
Aluminium silicate
What is the lustre of kyanite?
Glassy
What is the crystal form of kyanite?
Prismatic, bladed
What what is the chemical composition of Mica?
Potassium Magnesium Iron Aluminium Silicate Contains water (Dark mica)
Potassium Aluminium Silicate Contains water (White mica; muscovite)
What is the lustre of mica?
Glassy
What is the crystal form of Mica?
Tabular, Platy
What is the chemical composition of quartz?
Silicon dioxide
What is the lustre of quartz?
Glassy