WeatheringCrystals and Oxidation

Crystal FormationFive Requirements for Crystallization.1. Ingredients 2. Temperature3. Pressure4. Time5. Space

The right combination of ingredients, heat, and pressure must last long enough for the

minerals to crystallize. They also need room to grow.

Crystal Formation

Saturation-• Saturate- To charge with something to the

point where no more can be absorbed, dissolved, or retained

• Saturation - The act or process of saturating

Making Rock Candy

Crystal Formation Summary

• After viewing the video, in your journal, summarize the process in which crystals are formed.

• Include – Saturation (ingredients), Temperature (heating and cooling).

• Summary - As the water cools to room temperature again, the amount of sugar it can hold in suspension will return to the previous level. The excess sugar must come out of the solution and, as it does, it will crystallize.

Crystal Formation

• As the temperature of a liquid drops, the amount of solid ingredients it can hold in suspension drops as well.

• Inside the earth, the ingredients are more complex than our sugar solution. You will actually have different minerals crystallizing from the same solution at different temperatures.– Corundum might crystallize first. As the solution

continues to cool, topaz might form and later quartz.

Crystals and Chemical Weathering• Crystal Formation is another form of

chemical weathering.• The water flows in a rock and evaporates.

Crystals slowly begin to grow. Those crystals act like a wedge and crack the rocks.

Crystals and Chemical Weathering• Size of crystal formation is affected by the

temperature.• Crystals that form in warmer

temperatures are larger than those that form in colder temperatures.

Crystals and WeatheringFormed in cooler temperatures Formed in warmer temperatures

Sketch the examples of crystals formed in warm versus cooler conditions.

Oxidation

• Oxidation is a chemical process of combination and resulting reaction of any substances with oxygen.• Oxidation makes rocks softer. It is

similar to an iron bar rusting. Since there is a lot of iron in many rocks, oxidation often happens.

Examples of Oxidation

• When some fruit is cut, the oxidation causes it to brown.

• Vanadinite is an uncommon mineral. It is found in arid climates and forms by oxidation of primary lead minerals.

Examples of Oxidation

• Azurite is carbonate mineral, chemical formation is copper carbonate hydroxide. Commonly it associates with Malachite. The mixture of Azurite and Malachite is called Azurmalachite. It is an ore of copper. It forms by oxidation of copper ore.

Examples of Oxidation

• As you probably know, Lady Liberty was made out of copper. But over the years, oxidation has caused a green patina to cover that copper. As a result, the statue we know today looks very different from the symbol of freedom that our ancestors saw when they came to this country.

Examples of Oxidation

• Rust (iron oxide) is a form of oxidation when iron comes into contact with iron and oxygen and water.

Examples of Oxidation

• Using the examples, describe the affects of oxidation.

Oxidation and Temperature

• Temperature increases the rate of oxidation. This is because the molecules are moving around faster and having more collisions, so there are more opportunities for the reaction to occur.

• How might climate affect the rate of oxidation?