1. Forming Rocks & Minerals December 1, 2015 7 th grade Chapter 9.1, part 2

2. Meme Moment

3. Minerals Mineral: naturally occurring solid that can be formed by inorganic processes, has a crystal structure, and a defined chemical composition Defined chemical composition means that it’s a single type of molecule, so you can also call a mineral a substance 5 traits to define a mineral Dioptase (CuSiO 3 ·H 2 O)

4. 5 Traits of Minerals 1.Naturally occurring o You can make things that look like minerals in a lab, but they’re not “official” minerals unless they’re also found in nature. 2.Solid 3.Crystal Structure o Flat sides, sharp edges (based around prism shapes from math class!) 4.Forms by inorganic processes o You can sometimes form minerals in the body (e.g. kidney stone), but it’s not an “official” mineral unless you can also make it with things that aren’t plants or animals 5.Definite chemical composition o You can write a chemical formula for them

5. 3 Ways to Form Minerals Crystallization: the process of arranging atoms/molecules so that the substance has a definite crystal structure 1.From solutions 2.From cooling lava 3.From organic processes o To be considered a mineral, the same thing has to also form at other times by inorganic processes o E.g. Calcite can be made by clams and coral for their exoskeleton or in caves as stalactites (and other ways)

6. Solutions Not the same thing as fixing a problem! Solution: similar to a homogeneous mixture, but one substance is dissolved in another substance We’re usually talking about things dissolved in water, but it can be anything – technically doesn’t have to even be a liquid When substances leave a solution, crystallization occurs

7. What makes something leave a solution? Evaporation o If you slowly remove the water, it leaves behind the other substance. Bigger crystals instead of sandy particles if it’s slow and not shaken Cooling o Usually, hot water can dissolve more of a substance in the first place. If it gets cold, the substance no longer “fits” Chemical change o If you dissolve one substance and it slowly changes into something else, the new substance might not have the same solubility (a physical property )

8. Magma & Lava Magma is molten rock beneath the earth’s crust Lava is when it makes it to the surface Magma & lava contain a lot of oxygen (O) and silicon (Si), so they form a lot of silicates o Silicates make up most of the earth’s crust Type of mineral formed depends on speed, heat, pressure, elements present, etc Magma cools slowly Lava cools quickly, so it makes smaller crystals

9. Silicates Depending on how it cools & what else is present, silicates can form a bunch of different minerals because there are a bunch of different crystal structures possible

10. Where to find minerals Depending on how they’re made, some minerals are more common in certain areas If you are in an area with a lot of earthquakes, would you expect more or less minerals to be made from lava? If hot water with dissolved substances was pushed through a crack in a rock, what might form?