Igneous rocks
Igneous rocks are rocks that were hot magma that either got erupted out or got stuck in a vent in a volcano and cooled. When the lava cools inside a volcano it is called a intrusive rock. When it is cooling in a volcano it melts other minerals around it making it look like a bunch of rocks in one. An extrusive rock is when the lava gets erupted out of the volcano and cools really fast. It melts so fast it dose'nt have any time to melt anything around it.
SedImentary rocks
SedImentary rocks are when pebbles, sand, etc float to the bottem of a lake or a sea. The sand or pebbles sink to the bottem of a lake and sit there for millions of years and when they sit there for so long more sedIments pile on top of them and they get compacted into rocks. Thats not all that can happen though when rocks pile up on top of each other the presure cements the rocks together. Sometimes you can find fossils in limestone, shale and other sedimentary rocks.
Metamorfic rocks
Metamorphic rocks are rocks that can be made from both Igneous, Sedementary and other Metamophic rocks. Metamorphic are formed deep inside the earths crust where there is alot of heat and prussure. Metamorphic rocks change from one rock to another. The parent rock is the rock that it was befor it got changed. Foliated metamorphic rocks have layers. Non-foleated metamorphic rocks have no layers.
Hardness
The hardness test is well testing how hard the mineral is to help you identify the mineral. The way you do this is you use the mohs hardness scale. it have a hardness of 1 to 10 1 being talc and 10 being diamond. Hardness is one of the most important tests.
Luster
Another way that scientists identify minerals is by their luster (their shininess). Some minerals like gold or diamond appear shiny. it is another clue to their identity other minerals appeared dull. the shininess of the mineral depends on how the light is reflected from its surface if it shines like a polished metal surface is said to have metallic luster if mineral does not shine like metal it is called a nonmetallic luster. There is a scale for nonmetallic luster it goes Silky as the bottom pearly waxy greasy glassy and adamantine.
Streak
Streak is when you take the mineral and scratch it on a porcelain tile usually it leaves a mark on the tile but it doesn't always. If the rock didn’t leave a mark it would be harder than the porcelain tile. When you scratch the mineral on the porcelain tile it leaves a streak of the powder of what the rock is. a porcelain tile is a seven on the Mohs scale.
Color
There are lots of minerals that are the same color. Color is also one of the most attractive properties were mineral. The color can also help find out what the mineral is. There are lots of minerals that are the same color. the mineral depends on how way is reflected from the surface which shows you how shiny it is.