Minerals
Do you know what a mineral is? A mineral is a chemical element or compound that is naturally occurring and has a crystal structure. A rock is a material that is made of one or more chemicals. There are six different tests to identify what kind of mineral it is; these six teats are called the hardness, streak, color, fracture and cleavage, crystal structure, and luster.
Hardness
Hardness is an important test to identify what kind of mineral it is. Hardness is a measure of the minerals resistance to being scratched. Mohs scale hardness scale is 1 to 10.
Streak
The streak is the color of the powdered form of materials. Minerals that have a hardness greater than 7 do not have a streak on the tile. A streak test is a very good way to figure out whether a mineral is gold or pyrite. Gold would leave a golden streak and pyrite would leave a greenish, black, brownish streak.
Color
Color is one of the most attractive properties of a mineral. Color by it’s self can not identify what kind of mineral it is. One mineral may be found in several different colors.
Fracture and cleavage
The way a mineral breaks apart is another clue of what kind of mineral it would be. If a mineral breaks along smooth, or flat surfaces it is considered to be a cleavage. Mica is an example of a cleavage mineral. Not all minerals are cleavage some minerals are fracture that means they break along rough or jagged edges. An example of a fracture mineral would be Quartz.
Crystal structure
The six major Crystal Systems.
Minerals: Systems:
haltie: cubic
wulfenite: tetragonal
corundum: hexagonal
topaz: orthorhombic
gypsum: monoclinic
albite: triclinic
Minerals: Systems:
haltie: cubic
wulfenite: tetragonal
corundum: hexagonal
topaz: orthorhombic
gypsum: monoclinic
albite: triclinic
A crystal structure has straight edges, flat edges, and regular angles. Most of the minerals in the Earth's crust develop into extraordinary shapes.
Lustre
The shininess our lustre of a mineral depends on how light is reflected from it's surface. If a mineral shines like a polished metal surface it is metallic lustre. If a mineral does not shine it means it is non metallic.
Names of lustre:
adamantine
glassy
greasy
waxy
pearly
silky
Names of lustre:
adamantine
glassy
greasy
waxy
pearly
silky
Rocks
Sedimentary
Sedimentary rocks are made from sediments and chemical reaction. Sediments is loose material like bits of rock, minerals, plants, and animals. Sediments slowly settle on top of each other, sediments forming more layers. Sedimentary rocks are often formed in oceans or lakes. The process of squeezing together layers in sediments is called compaction. Pieces of sediments that are held together by other material is called cementation. Compaction is the weight upon layer by layer. Cementation creates a big packs of rocks together. Limestone, shalt, and other sedmientary rocks contain fossils like trilobite. Fossils are evidence of living organisims. Sedimentary rocks have fossilized shells, bones, scales, footprints, teeth, and leaves.
Metamorphic
A metamorphic rock have shiny mica particles. Metamorphic rocks are made when heat, pressure, or fluids change one type of rock into a different type of rock. Metamorphic rocks can be made from igneous, sedimentary rocks, or from other metamorphic rocks. The formation of metamorphic rocks is a long, slow process. Metamorphic rocks are always formed under the Earth's surface were all of the heat and pressure is. Hot watery fluids can flow into igneous, sedimentary, or metamorphic rocks and can change the rock physically and chemically. Rocks that have been changed into metamorphic rocks are called parent rock. Metamorphic rocks that have layers are called foliated. Foliated means having thin like layers. Metamorphic rocks that do not have any layers is called non foliated.
Igneous
Igneous rocks are called fire rocks and are formed either underground or above. Igneous rocks form when hot magma or lava cools and becomes solid. Magma is melted rock found deep below the Earth's surface were there is high temperatures. Rock that is cooled below the Earth's surface is called intrusive rock. Granite is one example of intrusive rock. Rock that forms when lava cools on the Earth's surface is called extrusive rock. Igneous rocks cool really quickly or really slowly.
Rock cycle
The rock cycle is the process in which rocks are continually are changed over long periods of time. Erosion is the transportation of sediments to other locations. The rock cycle is when other rocks turn into other kinds of rocks for example.. When there is weathering and erosion igneous rock truns into sediments, then when there is compaction and cementation the sediments turn into a sedimentary rock, a sedimentary rock can either go back to sediments or if there is heat and pressure it can trun into a metaorphic rock, the metamorphic rock will melt and trun into magma, and the magma will eventually cool down and turn into an igneous rock. Also a igneous rock can also turn into a metamorphic rock from heat and pressure.