How Minerals How Minerals FormFormMineralsMinerals

Chapter 4 Sec 2Chapter 4 Sec 2

Minerals Form in Two WaysMinerals Form in Two Ways

Crystallization of Crystallization of Melted Materials Melted Materials

(i.e. magma and lava)(i.e. magma and lava)

Crystallization of Crystallization of Materials Dissolved in Materials Dissolved in

Water Water (In Solution)(In Solution)

Crystallization: the process by which Crystallization: the process by which atoms are arranged to form a material atoms are arranged to form a material with a crystal shape…..with a crystal shape…..

Note: Fully formed crystals are rare- Note: Fully formed crystals are rare- most are only partially formed because most are only partially formed because they form the same time as othersthey form the same time as others

Crystallization of Melted Crystallization of Melted Materials (Magma & Lava)Materials (Magma & Lava)

1.1. Magma Cools inside the crust or Magma Cools inside the crust or lava hardens and cools on the lava hardens and cools on the surface of Earthsurface of Earth

2.2. These liquid crystals cool and These liquid crystals cool and form crystals (repeating pattern form crystals (repeating pattern of atoms- either elements or of atoms- either elements or compounds)compounds)

Size depends on ….Size depends on ….

3 Things Impact the Size of the 3 Things Impact the Size of the CrystalsCrystals

1.1. Rate at which magma/lava coolsRate at which magma/lava coolsSlow=large crystals-tend to be deep below the Slow=large crystals-tend to be deep below the

surfacesurface

Fast=small crystals-on or near surface- crystals Fast=small crystals-on or near surface- crystals dondon’’t have enough time to add more to the t have enough time to add more to the repeating patternrepeating pattern

2.2. Amount of Gas Magma ContainsAmount of Gas Magma ContainsLots of gas interferes with the atomLots of gas interferes with the atom’’s ability to s ability to

connect togetherconnect together

3.3. Chemical Composition of MagmaChemical Composition of MagmaCompounds form bigger crystals than elementsCompounds form bigger crystals than elements

A solution is… A solution is… A mixture in which one substance (the solute) is dissolved in another (the A mixture in which one substance (the solute) is dissolved in another (the

solvent).solvent).______________________________________________________________

Minerals can form 2 Ways from a SolutionMinerals can form 2 Ways from a Solution 1. materials dissolved in solution come out of 1. materials dissolved in solution come out of

solutionsolution 2. the solvent evaporates-leaving the minerals 2. the solvent evaporates-leaving the minerals

behindbehind

Crystallization of Materials Crystallization of Materials Dissolved in Water (in solution)Dissolved in Water (in solution)

1.1. Elements dissolve in hot water heated Elements dissolve in hot water heated by the magma and form solutionsby the magma and form solutions

2.2. Solution cools Solution cools

3.3. Elements and compounds leave the Elements and compounds leave the solution and crystallize into minerals, solution and crystallize into minerals, often forming veinsoften forming veins

– Vein-narrow channel or slab of Vein-narrow channel or slab of mineral that is different from mineral that is different from surrounding rocksurrounding rock

Mineral Veins:Mineral Veins:

Mineral Solutions also occur near the Mineral Solutions also occur near the mid-ocean ridge:mid-ocean ridge:

1.1. Water seeps down through cracks in ocean floorWater seeps down through cracks in ocean floor2.2. It is heated by magmaIt is heated by magma3.3. Elements from the crust are dissolved into Elements from the crust are dissolved into

solutionsolution4.4. Rush upward due to densityRush upward due to density5.5. Travels out of vents or chimneysTravels out of vents or chimneys6.6. Cold water helps minerals crystallizeCold water helps minerals crystallize7.7. Mineral deposits are found on the ocean floorMineral deposits are found on the ocean floor

Hydrothermal VentsHydrothermal Vents

Minerals Formed by Minerals Formed by EvaporationEvaporation

These minerals are formed when the water These minerals are formed when the water evaporates and leaves the mineral that was evaporates and leaves the mineral that was in solution behindin solution behind

Examples:Examples:– Deposits of Deposits of HaliteHalite formed when ancient formed when ancient

seas evaporatedseas evaporated– Also, Gypsum, calcite, and potassiumAlso, Gypsum, calcite, and potassium

Mineral Mineral ResourcesResourcesChapter 4 Sec 3Chapter 4 Sec 3

Uses of MineralsUses of Minerals

MetalsMetalsGemstonesGemstonesMaterial used to Material used to make useful productsmake useful products

GemstonesGemstones A gemstone is a hard, colorful mineral that A gemstone is a hard, colorful mineral that

has a brilliant or glassy luster. has a brilliant or glassy luster. Valued for their color, luster, durability, Valued for their color, luster, durability,

and because they are rare. and because they are rare. Called a gem once it is cut and polished.Called a gem once it is cut and polished. Used for jewelry, decoration, mechanical Used for jewelry, decoration, mechanical

parts, grinding and polishingparts, grinding and polishing

MetalsMetalsMinerals are the sources of some metals- Minerals are the sources of some metals-

aluminum, iron, copper, or silveraluminum, iron, copper, or silver

Useful for their unique properties of ductility, Useful for their unique properties of ductility, malleability, and strengthmalleability, and strength

Other Useful MineralsOther Useful Minerals FoodsFoods MedicinesMedicines FertilizersFertilizers Building materialsBuilding materials

Specific ExamplesSpecific Examples– talc=talcum powdertalc=talcum powder– Fluorite=used in aluminum and steelFluorite=used in aluminum and steel– Calcite=microscopesCalcite=microscopes– Quartz-used to make glass, electronic Quartz-used to make glass, electronic

equipment, and watchesequipment, and watches

OreOreA rock that A rock that contains a metal or contains a metal or other economically other economically useful mineraluseful mineral

Finding Useful MineralsFinding Useful Minerals

ProspectingProspecting– A prospector is anyone who searches, or A prospector is anyone who searches, or

propsects, for an ore depositpropsects, for an ore deposit– Look for EarthLook for Earth’’s features- such as types of s features- such as types of

rocks on the surface, plants growing, and rocks on the surface, plants growing, and types of elements found in water sourcestypes of elements found in water sources

Extracting Useful MineralsExtracting Useful Minerals 3 types of mines3 types of mines

– Strip mineStrip mine Earth moving equipment scrapes away soil to Earth moving equipment scrapes away soil to

expose oreexpose ore

– Open pit mineOpen pit mine Miners dig an open pit mine to remove deposits and Miners dig an open pit mine to remove deposits and

then follow them below the surface (approx 1 km then follow them below the surface (approx 1 km wide and deep)wide and deep)

– Shaft mineShaft mine To follow veins miners dig a network of tunnels To follow veins miners dig a network of tunnels

(shaft mines)(shaft mines)

Mining can cause quiet a bit of damage to Mining can cause quiet a bit of damage to the environmentthe environment

SmeltingSmelting

The process by which an ore is The process by which an ore is melted to separate the useful metal melted to separate the useful metal from other elements that the ore from other elements that the ore containscontains