Title: How Minerals Form In general, minerals form in two ways:
1 How Minerals FormIn general, minerals form in
two ways
- By crystallization of magma lava
- By crystallization of materials dissolved in
water.
2Crystallization is the process by which atoms are
arranged to form a material with a crystal
structure.
3A geode is a rounded hollow rock that is often
lined with mineral crystals.
4Minerals From Magma Lava
- Minerals form as hot magma cools inside the crust
or when lava hardens on the surface.
5The size of the crystal depends upon several
factors
- The rate (speed) at which the molten material
cools. - The amount of gas in the molten material.
- The chemical composition of the molten material
(or what elements/chemicals make up the molten
rock.
6Magma deep inside the earth takes thousands of
years to cool. Slow cooling results in large
crystals.
7Magma close to the earths surface or lava that
cools on the surface will cool more quickly.
8Rapid cooling results in small crystals.sometimes
microscopic.
9Minerals From Solutions
- Elements/Compounds
- that form minerals
- may sometimes be
- dissolved in water to
- form a solution.
10When elements/compounds that are dissolved in
water leave a solution, crystallization can occur.
11Minerals Formed by Evaporation
- Some minerals form when solutions evaporate.
Large deposits of halite in the USA formed this
way.
12Minerals From Hot Water Solutions
- Underground, magma
- can heat water to high
- temperatures.
- Elements/Compounds
- may become dissolved
- in this hot solution.
13When the water solution cools the elements and
compounds crystallize as minerals.
14Pure metals that crystallize from hot water
solutions underground often form veins.
15A vein is a narrow channel or slab of a mineral
that is different from the surrounding rock.