Minerals

Pre-Assessment

1. The two most abundant elements in common minerals are A. calcium & manganeseB. silicon & oxygenC. iron & magnesiumD. carbon & potassium

Answer

B

2. The heft or relative weight of a mineral sample is directly related to the mineral's A. lusterB. cleavageC. densityD. hardness

Answer

C

3. A mineral that splits into even sheets shows which of the following properties? A. perfect fractureB. consistent streakC. good cleavageD. triclinic crystal shape

Answer

C

4. Which of the following follows ALL the rules of being a true mineral? A. coalB. concreteC. steelD. quartz

Answer

D

Do you Know Any Examples of Minerals we SEE or USE everyday?

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Ex: Salt Ex: Graphite

Ex: Talc Ex: Gypsum

What Determines a Mineral?

What defines a Mineral?• Minerals must be naturally occurring which means

they are formed by nature, not by man• Minerals must be solid• Minerals must have an orderly crystal structure which

means that atoms always have the same chemical arrangement

• Minerals have a definite chemical composition which means they are always made of the same elements

• Minerals are generally inorganic which means they are not made by living things (this gets tricky with the mineral Calcite)

Salt is consistently made of two elements: Sodium (Na) and Chlorine (Cl) and because of this, it has a specific chemical structure. This structure can then be seen in the large pieces of salt below.

How do Minerals Form?The 4 main processes by which minerals form:

1. Crystallization from Magma2. Precipitation3. Changes in Pressure and Temperature4. Hydrothermal Solutions

(leave some room under each example for explanations)

Crystallization from Magma• Magma is molten rock

deep within Earth; as it cools elements combine to form minerals

• Examples of minerals formed under these conditions include feldspar, quartz, muscovite, and hornblende

Precipitation• There are lots of dissolved substances in

Earth’s rivers, lakes, ponds, and oceans• When water evaporates, then the dissolved

substances combine to form minerals

Stalactites and Stalagmites Calcite

Changes in Pressure & Temperature

• When existing minerals are put under intense heat and pressure (usually b/c they are deep within the Earth) they can form new minerals

** Basically, the heat and pressure makes the old mineral unstable so it can rearrange and reassemble its chemical bonds, this makes a new mineral

Ex: talc and muscovite

Hydrothermal Solutions• Very hot mixture of water and dissolved substances

(temperatures usually 100°C - 300°C)• When hot mixture comes into contact with

minerals, chemical reactions take place and form new minerals

Bornite Chalcopyrite

Today we will be doing a DENSITY Lab, so let’s learn/review the concept:

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Density

Density compares the mass of an object to its volume

D = __Mass_(g)__ Volume (cm3)

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Mass = the amount of matter in an objectUnit for Mass is grams. (g)

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Volume = the amount of space a (3 D) object takes up Units for Volume are mL or cm3

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For people who don’t like Math!

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When finding Mass:• Unit = grams (g)• Use a Triple Beam Balance

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Reading a Triple Beam Balance

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What about the volume of this?

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You don’t need a ruler but a graduated cylinder for the volume of liquids or irregular solids.

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Read the Meniscus on the graduated cylinder below:

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What is the Volume of the Rock?

Any Questions?

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