quiz 4 rocks

Rocks

Hard pieces of the earth’s surface

Sediment

Small bits of weathered rock

Sedimentary rock

Forms when layers of sediment are pressed together and harden

Limestone

Forms mainly from shells of sea animals

Sandstone

Sedimentary rock that is made when layers of sand get pressed together

Shale

Forms from layers of mud

Ingeous rock

Forms when melted rock cools

Volcano

Opening in the earth that allows melted rock to come to the surface

Lava

Melted rock that comes out of a volcano

Obsidian

Smooth igneous rock

Looks like glass

Granite

Forms when melted rock cools slowly, often speckled

Mount Rushmore

Famous granite mountain in South Dakota, 4 presidents faces

Metamorphic rock

Forms when igneous or sedimentary rocks are changed by great heat and pressure

Limestone

Soft sedimentary rock, placed under heat and pressure becomes marble

Slate

Forms from shale

Can be split into thin sheets

Gneiss

formed from granite under heat and pressure

Minerals

Solid materials in nature that were never alive

Friedrich Mohs

Studied minerals and put them in order from softest to hardest.

Mohs Hardness scale

Ranks minerals from 1 to 10. Uses scratch test. Scale helps identify minerals

Talc (1)

Very soft mineral, used to make a soft powder, almost every other mineral can scratch it

Diamond (10)

Very hard mineral, can cut or scratch all other minerals

Crystal

Most minerals form theses.

Solid material whose particles are arranged in a special pattern

Streak test

Helps identify mineral, rub mineral on light colored tile, the streak helps them know what mineral it is.

Iron

Mineral that your body needs to work properly

Calcium

Another mineral you need found in milk

Precious minerals

Hard to find or hard to get

Gold and silver

Gem

Formed when crystals of some precious minerals are cut and polished to reflect light. Example is a diamond

Common mineral

Easier to find

Halite (salt) , graphite (lead in pencils) , quartz (glass, computers, cellphone)

Properties of minerals

Hardness, crystal shape, color and streak

3 Rock groups

Sedimentary, igneous, metamorphic