Minerals

To be a mineral, a substance must be an inorganic, naturally occurring solid, with a set parameter of chemical formulas and a crystalline structure.
Minerals occur naturally on rocky planets and form the building blocks of rocks. They are non-living, solid and, like all matter, are made of atoms of elements. There are many different types of minerals and each type is made of particular types of atoms. The atoms are bonded together and arranged in a special way called a crystal lattice, a network of atoms. The lattice of atoms is what gives a mineral its crystal shape.
Different types of minerals have different crystal shapes. Most minerals can grow into crystal shapes if they have enough space as they grow. But most of the time there are so many different crystals growing in the same space that they all compete for space and none of the crystals is able to grow very large.

There are two main ways that new crystals of minerals grow. Either they form when molten rock, called magma below a planet’s surface and lava above, cools and changes state from a liquid to a solid allowing atoms to bond together into mineral crystals. Or, some minerals grow when water, that is rich with dissolved elements, evaporates and the atoms in the water get very close together, eventually bonding together forming solid minerals.

The special shapes of minerals are not the only difference between them. Minerals can be identified by other physical properties as well. Each type of mineral has its own unique set of characteristics.

Chemical Properties of a Mineral- Mineral Families - igneous, sedimentary, and metamorphic

- Igneous Rock- Rocks formed when hot magma in the Earth cools rapidly and becomes a solid. Magma forced out of the Earth’s surface makes extrusive igneous rocks (obsidian and pumice) while magma that fills in between layers of rocks and cools slowly is called intrusive igneous rocks (granite).


- Sedimentary Rock- A rock formed from materials which have been deposited as a sediment in water or on land. They include rocks formed from fragments of pre-existing rocks, deposits formed from the hard parts of organisms and salts deposited from solution.

- Metamorphic Rock- Formed when existing rocks lying deep below the Earth's surface are subjected to high temperatures, high pressures, chemically active fluids, or a combination of these agents, causing the rocks' crystal structure to change.

Physical Properties of Minerals-

Color- the color that the mineral is.
http://www.kingopal.com.au/images/crystal_opal.jpg
http://www.kingopal.com.au/images/crystal_opal.jpg

Hardness-Hardness is one measure of the strength of the structure of the mineral relative to the strength of its chemical bonds.
http://volcano.oregonstate.edu/vwdocs/vwlessons/lessons/Slideshow/Show2/rosequartz8.jpg
http://volcano.oregonstate.edu/vwdocs/vwlessons/lessons/Slideshow/Show2/rosequartz8.jpg

Cleavage or Fracture- the way a mineral breaks
http://www.mrsciguy.com/sciimages/basal.jpg
http://www.mrsciguy.com/sciimages/basal.jpg

Crystalline Structure- helps determine such physical properties as hardness, color, and cleavag
e
http://www.pengellytrust.org/museum/aragonite/images/aragonite_crystalline_structure.gif
http://www.pengellytrust.org/museum/aragonite/images/aragonite_crystalline_structure.gif

Diaphaneity or Amount of Transparency
http://geology.com/minerals/photos/quartz-conchoidal-482.jpg
http://geology.com/minerals/photos/quartz-conchoidal-482.jpg

Magnetism
http://z.about.com/d/geology/1/0/n/T/1/minpicmagnetite.jpg
http://z.about.com/d/geology/1/0/n/T/1/minpicmagnetite.jpg

Luster
http://z.about.com/d/geology/1/0/z/C/1/variscite500.jpg
http://z.about.com/d/geology/1/0/z/C/1/variscite500.jpg

Specific Gravity

Streak
http://www.theimage.com/geology/notes3/streakplate.jpg
http://www.theimage.com/geology/notes3/streakplate.jpg

Special properties-


  • Magnetite is magnetic.
  • Flourite glows under ultraviolet light.
  • Halite tastes salty.
  • Sulfur has an unusual odor.
  • Calcite fizzes when hydrochloric acid is added to it.
  • igneous rocks are also called "lava rocks"

References