| A | B |
|---|
| crust | Loose soil and rock fragments covering the Earth. |
| outcrop | Bedrock which is exposed at the Earth's surface. Often seen in mountains, cliffs and roadcuts. |
| soil | a combination of finely broken up bedrock and organic matter. |
| mineral | A solid inorganic substance with definite physical and chemical properties, containing one or more elements. |
| hardness | The ability of a mineral to resist scratching. Measured on a scale of 1 (Talc) - 10 (Diamond). |
| cleavage | A property of minerals which break in definite directions along smooth surfaces. Mica is an example. |
| fracture | A property of minerals which do not exhibit cleavage, but break leaving splintered or jagged surfaces. |
| streak | The color of a mineral's powder after rubbing it on an unglazed porcelain plate (streak-plate). |
| luster | The way a mineral reflects light, making it look like a metal or a non-metal. |
| color | One of the physical properties of a mineral used to identify it, but not the most reliable way. |
| crystal form | The characteristic shape of a mineral. |
| density | The ratio of the mass of a substance to its volume. |
| acid test | A test for the presence of carbonates. A drop of HCl (hydrochloric acid) placed on the mineral will cause bubbling if carbonates are present. |
| igneous | Formed when rock is heated to a liquid state (magma) and then cools and hardens. Granite, Obsidian and Basalt are examples. |
| magma | Hot, liquid (molten) rock found beneath the Earth's crust. |
| sedimentary | A type of rock formed when layers of rock fragments build up and become cemented together by extreme pressure. Sandstone, Limestone and Gypsum are examples. |
| metamorphic | Rock formed from igneous or sedimentary rock subjected to intense heat, pressure or chemical action. Slate, Gneiss and Marble are examples. |
| rock cycle | The transformation of one rock type to another. |
| ocean floor | The fairly level portion of land deep beneath the ocean which stretches from one continent to another. |
| continental shelf | The first section of the ocean floor which slopes gently from the shore. Formed by erosion of crust from the land. |
| continental slope | A steeper region of the ocean floor which begins where the continental shelf ends. |
| trenches | Deep valleys in the ocean floor. |
| weathering | A physical, chemical or biological processes which cause rock on the surface of the Earth to crumble or decay. |
| physical | Weathering which breaks rock into smaller pieces without changing its chemical makeup. Freezing water is a common cause. |
| chemical | Weathering which occurs when substances in water or the atmosphere react with rock minerals. Water and acid rain are two examples. |
| biological | Weathering which occurs when plants and animals break down rocks. |
| erosion | Carrying away the rock fragment material created by weathering. Winds and water flow are important erosion agents. |
| glacier | A large mass of ice found all year round at high altitudes (mountains) or high latitudes (polar regions). |
| terminal moraine | A large pile of rock left at the melting end of a glacier. |
| fossils | The remains or imprints of ancient animals or plants trapped in layers of sedimentary rock. |
| plate tectonics | A theory that the earth's crust is split into a number of blocks or 'plates' which move slowly over the surface of the Earth. |
| continental drift | The movement of large sections or 'plates' of the earth's crust caused by the flow of material in the mantle. |
| mantle | A layer of the earth's interior between the core and the crust. It is semi-solid melted rock. |
| mountain | A feature of the Earth's surface created by folding or faulting of the earth's crust, or by volcanic action. |
| volcano | An opening in the earth's crust through which molten (liquid) rock called magma may flow. |
| lava | Magma which comes to the earth's surface and solidifies. |
| plains | Broad, flat regions of undisturbed sedimentary rock, found at low elevations. |
| plateaus | Areas of undisturbed sedimentary rock that are found at elevations greater than 1000 meters. |
| radioactive dating | A method used to determine the age of rocks based on measuring the amount of decay by radioactive elements in minerals. |
| half-life | The amount of time required for one half of the starting amount of an element to decay. |
| index fossils | Fossils of organisms which were abundant, but lived for only a short period of time, so their presence in a rock indicates its age. |
