Learning Target.. I Can.. Identify the differences between a mineral and a rock.

Transcription

1 Rocks and Minerals

2 Learning Target.. n I Can.. Identify the differences between a mineral and a rock.

3 What is a mineral? A mineral o Is a Inorganic solid formed in nature (Inorganic -- not living or ever been living. It is not formed by plants or animals) o Has a characteristic fixed chemical composition o Has distinctive physical properties o Has a Crystalline structure (-- an orderly arrangement of atoms)

4 Crystals Minerals with some solid, geometric shape to them are called crystals. They are produced by a repeating pattern of atoms that is present throughout the mineral. Crystals can be made from different elements: (ex: diamonds are made from carbon) (salt is made from the elements sodium and and chlorine.

5 Crystals cont d A crystal s shape is determined by the arrangement of the atoms within the crystal. A crystal s color is determined by the elements that are mixed in. Crystals are not just what we think of as jewelry. You actually eat many different types of crystals( such as salt, sugar, baking soda)

6 Minerals are more common than you think. Currently, about 4,000 minerals have been identified, and 50 to 100 new minerals are discovered each year!! We use them in our everyday households such as metal pots and pans, salt shakers, dishware, and even glassware!!!

7 How do minerals form? They form in several ways: 1. From melted rock inside the Earth called magma o As it cools the atoms combine in orderly patterns to form minerals 2. From magma that reaches Earth s surface, called lava o As it cools the atoms combine in orderly patterns to form minerals 3. Evaporation of dissolved minerals 4. From precipitation *water can hold dissolved minerals.

8 Properties of Minerals include: Color Streak Luster Hardness Cleavage & Fracture Density Specific Gravity Special Properties

9 Color: Not Mineral Specific It s the LEAST reliable way to classify a mineral!!

10 Luster: (shininess) It s describes how minerals Metallic Non-metallic reflect light

11 Streak: Is the mineral in it s powdered form of a mineral NOTE: The color of a mineral s streak is not always the same as the color of the mineral sample.

12 Cleavage & Fracture Describes how different types of minerals break in different ways. Cleavage is the tendency of some minerals to break along smooth, flat surfaces. Biotite Mica Calcite Fracture is the tendency of some minerals to break unevenly along curved or irregular surfaces Mica

13 Hardness: A mineral s resistance to being scratched. This is tested using the Mohs Scale of hardness (pg. 272)

14 The Mohs scale was founded by an Austrian geologist: Fredrich Mohs.

15 Ooohhh!! Diamonds! Diamonds are the hardest known mineral (10 on Mohs Hardness Scale) They are formed very deep in the Earth and at great pressure It takes 250 tons of Earth to obtain a 1.00 Ct Diamond! It takes 1405 degrees of heat to burn a Diamond! Only Diamonds can Scratch or Polish another Diamond! Diamonds come in wonderful fancy colors like, Pink, Blue, Green, Champagne, Black, Chocolate, Yellow, Red, Gray, and even Purples! (such as the famous HOPE diamond, which is blue!!)

16 Did You Know? The largest diamond in the world is the Cullinan diamond weighing 3,106 carats! It was cut into 105 separate diamonds.

17 Density and Specific Gravity Density is the measure of how much matter is in a given amount of space. Density is a ratio of an object s mass to its volume. (D= m/v) Different minerals have different densities. A mineral s Specific Gravity compares the weight of a mineral with the weight of an equal volume of water.

18 Special Properties Some properties are particular to only a few types of minerals. - The properties shown on the next slide can help you quickly identify some minerals.

19 Special Properties

20 Gems are rare minerals that can be cut and polished, giving them a beautiful appearance Ideal for jewelry Are rare and are therefore valuable Must be made under tremendous amounts of heat and pressure, deep in the Earth s mantle It takes a certain kind of volcanic eruption to bring diamonds close to the surface

21 Ores A mineral is called an ore if it contains enough of a useful substance that it can be sold for a profit Metals that people use, such as: Iron used to make steel comes from hematite Lead for batteries comes from galena Magnesium in vitamins comes from dolamite In order to obtain these ores, they must be mined

22 Learning Target.. n I Can.. Use a table of physical properties to classify minerals.

23 What is a Mineral?

24 What is a mineral? A mineral is a naturally formed, inorganic solid, with a fixed chemical composition, that has a definite crystalline structure.

25 What is a mineral? u Solid t Cannot be a liquid or a gas u Naturally Occurring t Found in nature, not man-made u Inorganic t Is not living nor has ever been living u Fixed chemical composition t Has a definite chemical formula, most are formed from two or more elements, but some minerals consist of one element ex. Au u Crystalline structure t A definite structure in which atoms are arranged in a geometric pattern

26 Questions to ask yourself when determining if an item is a mineral or not: u Is it non-living material? u Is it a solid? u Is it formed in nature? u Does it have a crystalline structure?

27

28 Gold

29 Fossil

30 Topaz

31 Bones

32 Granite

33 Quartz

34 Pearls

35 Talc

36 Icebergs

37 Diamond

38 Coal

39 Rock Salt

40 And the answers are n Minerals a) Gold b) Topaz c) Quartz d) Talc e) Iceberg* n Non-Minerals a) Wood - once living b) Fossils once living c) Bone - living material d) Granite - intrusive igneous rock e) Pearls made by oysters f) Diamonds f) Coal - Sedimentary rock g) Rock Salt Sedimentary rock *FYI: According to the MA (International Mineral Association) ice is listed as a mineral!

41 Quick Check.. n Can you name all eight physical properties of minerals? n Color n Luster n Streak n Hardness n Cleavage & Fracture n Density n Specific Gravity n Special Properties