Please enable JavaScript.
Coggle requires JavaScript to display documents.
6.3 Minerals (Minerals (Rocks are made up of minerals, many minerals can…
6.3 Minerals
Minerals
Rocks are made up of minerals, many minerals can dissolve in water and so these minerals may also be found as aqueous solutions in groundwater, lakes and the oceans
-
A mineral is a chemical substance which is a naturally occuring solid that has not been made by animal, plant or any other type of organism
Many precious gemstones, or gems, are also mineral compounds (rubies and emerald)
Not all solids found in the Earth are minerals, solids formed by organisms are not classified as minerals
Fossil fuels like coal and ail are not minerals - they were formed by the decay of long-dead organisms, not by natural processes of the Earth itself
Ores
Copper can be found as an element, while the other ores are found as compounds of copper bonded to other elements
-
-
-
Titanium oxide, TiO2 can be :
used as a whole mineral to colour paints white
separated into the element titanium metal, Ti, and oxygen, O2, the titanium can then be used to make steel alloys
Properties of minerals
-
Hardness
Determining the hardness can be by testing:
what can scratch an unknown
mineral which minerals can be scratched by the unknown mineral
-
-
Lustre, colour and streak tests
Colour is very useful when prospecting (searching) for minerals. For example, gold shows up as a yellowish colour in rock and soil.
Lustre is how shiny a mineral is. Lustre can be useful when you are out prospecting for minerals. For example, gold has a bright shiny surface when clean or wet. Lustre is divided into many categories. Examples are glassy, waxy, metallic and dull
The appearance of a mineral can give a good idea of what it might be, the way a mineral looks can be analysed in three ways
Streak is the colour left behind when you try to scratch an unglazed white tile with the mineral. The streak is often different from the colour of the mineral itself. For example, iron pyrites (commonly known as ‘fool’s gold’) looks very similar to real gold. They both have a similar golden colour. However, fool’s gold has a greenish-black streak, while real gold has a gold streak
-