5 Element or compound with a definite chemical composition
6 Orderly arrangement of atoms; all minerals are crystalline solids
7 Crystal—solid with atoms arranged in orderly, repeating patterns
8 Some crystals form from magma, hot melted rock below the Earth’s surface.
9 When magma cools slowly, crystals are large. When magma cools quickly, crystals are small.
10 Crystals can form from solutions as water evaporates or if too much of a substance is dissolved in water.
11 Mineral groups are defined by their composition. Silicates contain silicon, oxygen, and one or more other elements; they include most common rock-forming minerals.Silicon and oxygen are the two most abundant elements in Earth’s crust; they form the building blocks of many minerals.
12 DISCUSSION QUESTION:What processes can cause crystals to form?
13 DISCUSSION QUESTION:What processes can cause crystals to form?Crystals form from cooling magma, from evaporating solutions, and from solutions in which too much of a substance is dissolved.
14 Mineral Identification Color and appearance are not enough to distinguish most minerals.
15 Hardness is a measure of how easily a mineral can be scratched; the Moh’s scale compares mineral hardness.
16 Talc - easily scratched by the fingernail Gypsum - just scratched by the fingernailCalcite - scratches and is scratched by a copper coinFluorite - not scratched by a copper coin and does not scratch glassApatite - just scratches glass and is easily scratched by a knifeOrthoclase - easily scratches glass and is just scratched by a fileQuartz - (amethyst, citrine, tiger's-eye, aventurine) not scratched by a fileTopaz - scratched only by corundum and diamondCorundum - (sapphires and rubies) scratched only by a diamondDiamond - scratched only by another diamond
27 The way a mineral reflects light is its luster. Luster can be metallic or nonmetallicNonmetallic lusters include dull, pearly, silky, and glassy.
28 Specific gravity is the relationship between a mineral’s density to the density of water. If the specific gravity is larger than one it will sink in water, if it is smaller than one it will float in water.
29 Streak is the color of a mineral in powdered form, but the streak test is useful only for minerals softer than the streak plate.
30 The way a mineral breaks can be a distinguishing characteristic. Minerals withcleavage breakalong smooth,flat surfaces.
31 Minerals with fracture break with uneven, rough, or jagged surfaces.
32 Some minerals have unique properties that involve light or magnetism.
33 DISCUSSION QUESTION:What are five properties that could be examined to identify a mineral?
34 DISCUSSION QUESTION:What are five properties that could be examined to identify a mineral?hardness, luster, specific gravity, streak, cleavage, and fracture
35 Gems—rare and beautiful minerals that are highly prized The Cullinan diamondand the Hope diamondare famous historical gems.Gems have industrialapplications in abrasives,lasers, and electronics.
36 Minerals can contain other useful elements. An ore is a mineral or rock containing a substance that can be mined at a profit.Elements must be refined, or purified, from ores.
37 Some elements dissolve in fluids, travel through weaknesses in rocks, and in those weaknesses form mineral deposits called vein mineral deposits.
38 Titanium is a useful element derived from the minerals ilmenite and rutile.
39 Mica is an example of a mineral with the characteristic of cleavage, Mica is an example of a mineral with the characteristic of cleavage, because it can be separated into sheets.
40 Graphite is one of the softest minerals and is used in pencils.
41 Sulfur is a bright yellow mineral with Sulfur is a bright yellow mineral with the distinctive odor of spoiled eggs.