Unit 1 Lesson 2 Minerals

Minerals What do minerals have in common? Unit 1 Lesson 2 – Minerals What do minerals have in common? Not all minerals are sparkling gems, but they all have certain characteristics in common. A mineral is a naturally occurring, inorganic solid with a definite crystalline structure and chemical composition. Minerals Definite Chemical Composition Naturally Occurring Crystalline Structure Inorganic 2

What do minerals have in common? Unit 1 Lesson 2 – Minerals What do minerals have in common? All minerals contain one or more elements, which are pure substances that cannot be broken down into simpler substances by chemical means. Each element is made up of one kind of atom, the building block of matter. Stable particles that are made up of strongly bonded atoms are called molecules. 3

What do minerals have in common? Unit 1 Lesson 2 – Minerals What do minerals have in common? A substance made up of molecules of two or more different elements is called a compound. The chemical composition of a mineral is determined by the element or compound that makes up the mineral. A mineral composed of only one element is called a native element. 4

Oxygen Atoms Silicon Atom Oxygen Atoms Unit 1 Lesson 2 – Minerals The mineral quartz is made up of the compound SiO₄, where 1 silicon atom forms a bond with 4 oxygen atoms. Oxygen Atoms Silicon Atom Oxygen Atoms 5

What do minerals have in common? Unit 1 Lesson 2 – Minerals What do minerals have in common? Matter is anything that has mass and volume. Mass is the amount of matter in an object. Volume refers to the amount of space something takes up. All minerals are solid, meaning each has a definite volume and shape. 6

All minerals are naturally occurring. Unit 1 Lesson 2 – Minerals What do minerals have in common? All minerals are inorganic, which means they are not produced by living things or from the remains of living things. All minerals are naturally occurring. 7

What do minerals have in common? Unit 1 Lesson 2 – Minerals What do minerals have in common? All minerals form crystals, which are solid geometric forms produced by a repeating pattern of atoms or molecules. 8

How are minerals formed? Unit 1 Lesson 2 – Minerals How are minerals formed? The type of mineral that forms depends on the elements present in the area and the temperature and pressure. Many minerals form from magma, which is molten rock inside Earth. As magma cools, the atoms join together to form different minerals. Minerals also form from lava, which is molten rock that has reached Earth’s surface. Quartz and feldspar are examples of minerals that form from magma and lava Feldspar Quartz 9

Garnet Serpentine Many minerals form by metamorphism. Unit 1 Lesson 2 – Minerals Many minerals form by metamorphism. High temperature and pressure within Earth cause new minerals to form as bonds between atoms break and reform with different atoms. Minerals formed by metamorphism are generally harder than other minerals because they are formed by extreme heat and pressure. Garnet and serpentine are examples of metamorphic minerals Garnet Serpentine 10

Halite Calcite Minerals also form from solutions. Unit 1 Lesson 2 – Minerals Minerals also form from solutions. Water usually has substances dissolved in it. As it evaporates, these substances form into solids and come out of solution, or precipitate. As hot water cools, dissolved substances may precipitate out of solution. Halite and calcite are examples of minerals that precipitate out of solution. Halite Calcite 11

How are minerals classified? Unit 1 Lesson 2 – Minerals How are minerals classified? Minerals are usually classified based on their chemical composition as silicate or nonsilicate minerals. Most common minerals are silicate minerals, making up 95% of Earth’s crust. They contain a combination of silicon and oxygen. Most silicate minerals are formed from silicate tetrahedrons, each made of one silicon atom bonded to four oxygen atoms. Tetrahedron 12

How are minerals classified? Unit 1 Lesson 2 – Minerals How are minerals classified? Nonsilicate minerals are minerals that do not contain the silicate tetrahedron building block. They may contain silicon OR oxygen, but not both. Groups of nonsilicate minerals include: native elements (gold, graphite) halides (fluorite, cryolite) sulfates (barite, gypsum) carbonates (calcite, aragonite) oxides (periclase, ice) sulfides (galena, pyrite) 14

What properties can be used to identify minerals? Unit 1 Lesson 2 – Minerals What properties can be used to identify minerals? Minerals can be identified by their physical and/or chemical properties. Physical properties are properties that can be observed without changing the identity of the substance. Examples: Color, density, mass, volume, streak Chemical properties are properties that can only be observed by changing the identity of the substance. Examples: Reactivity & flammability 15

Unit 1 Lesson 2 – Minerals Color. Even though color is helpful, it is not the best or the only way to identify a mineral. Streak. Streak is color of the powdered form of a mineral. It is found by rubbing it against a white or black tile streak plate. 16

Unit 1 Lesson 2 – Minerals Luster. Luster is the way the surface of a mineral reflects light. The two main types of luster are metallic and nonmetallic. They are then broken up into multiple sub-types. 17

Metallic Luster Nonmetallic Lusters Minerals with metallic luster have the look of polished metal. Some surfaces will also work as a reflective surface. Nonmetallic Lusters kaolinite Minerals with Dull (or earthy) luster exhibit little to no luster due to coarse granulations which scatter light in all directions. There is a distinction between dull and earthy minerals, with the earthy being coarser, and having even less luster. (kaolinite, orthoclase) orthoclase

muscovite Minerals with Pearly luster consist of thin transparent co-planar sheets. Light reflecting from these layers give them a luster reminiscent of pearls. Such minerals possess perfect cleavage. (muscovite, biotite mica) amber Minerals with Resinous luster have the appearance of resin or (smooth surfaced) plastic. A principal example is amber, which is a form of fossilized resin. (amber) gypsum Minerals with Silky luster have a parallel arrangement of extremely fine fibers, giving them a luster reminiscent of silk. (asbestos, ulexite, gypsum). opal Minerals with Greasy luster resemble fat or grease. A greasy luster often occurs in minerals containing a great abundance of microscopic inclusions. Many minerals with a greasy luster also feel greasy to the touch. (opal, jadeite)

sphalerite Minerals with Submetallic luster have similar luster to metal, but are duller and less reflective. A submetallic luster often occurs in near-opaque minerals that have refractive tendencies. (sphalerite, cuprite) quartz Minerals with Vitreous luster look similar to glass. (The term is derived from the Latin for glass, vitrum.) This type of luster is one of the most commonly seen, and normally occurs in transparent or translucent minerals. (quartz, ice) jade Minerals with Waxy luster have a luster resembling wax. (jade, chalcedony)

Unit 1 Lesson 2 – Minerals Cleavage. Cleavage is the tendency of a mineral to split along specific planes of weakness to form smooth, flat surfaces. A mineral with cleavage breaks along flat surfaces that generally run parallel to planes of weakness in the crystal structure. 21

Unit 1 Lesson 2 – Minerals Fracture. Fracture is the tendency for minerals to break unevenly, along curved or jagged surfaces. 22

Unit 1 Lesson 2 – Minerals Density. Density is the amount of matter in a given amount of space. It can be used to tell many similar-looking minerals apart. Hardness. Hardness is a mineral’s resistance to being scratched. Mineral hardness is compared using the Mohs hardness scale. Special Properties. Magnetism Reactivity Tenacity Odor Taste Flammability 23

Did you know? Many useful substances come from minerals. Unit 1 Lesson 2 – Minerals Did you know? Many useful substances come from minerals. The metal titanium comes from several minerals, including rutile. Titanium is very valuable because it resists corrosion and is as strong as steel, but is much lighter than steel. 25