Earth Science - Rocks and Minerals

mineraloids

substances like coals, pearls, and obsidian

Rock

a substace that contain one or more minerals or mineraloids

Precipitation

Ions in solution come together to form solid minerals

saturation

the point at which a solvent cannot hold any more solute

Magma

molten rock with freely moving ions

Lava

when magma is emplaced at depth or extruded onto the surface

Calcite

The most common mineral precipitated by organisms

aragonite

Calcite is often precipitated by organisms as a polymorph called..

Polymorphs

are crystals with the same chemical formula but different crystal structures

chert

when marine organisms die the shells accumulate on the ocean floor and can form the sedimentary rock

Silicate

form the largest group of minerals on Earth

Olivine

primary mineral component in mantle rock such as peridotite and basalt

fayalite

pure iron end-member of olivine

forsterite

pure magnesium end-member of olivine

Pyroxene

is another family of dark ferromagnesian minerals

Augite

A common member of the pyroxene family

Sheet silicates

are built from tetrahedra which share all three of their bottom corner oxygens thus forming sheets of tetrahedra with their top corners available for bonding with other atoms

phyllosilicates

another name for micas and clays which are common types of sheet silicates

Mica minerals

are usually found in igneous and metamorphic rocks

Clay minerals

are more often found in sedimentary rocks

biotite & muscovite

frequently found micas

ferromagnesian silicate mineral

Biotite mica has more iron and magnesium and is considered a

Felsic

a contraction formed from feldspar

Clay

occur in sediments formed by the weathering of rocks and are another family of silicate minerals with a tetrahedral sheet structure.
hydrous aluminum silicates

kaolinite

a type of clay that has a structure like an open-faced sandwich

potassium containing

the type of feldspar abundant in continental crust

Sodium containing

the type of feldspar abundant in oceanic crust

Framework silicates

Feldspar and quarts are considered

Quartz

the most abundant mineral on earth's surface

Feldspar

the most abundant mineral in the earth's crust

plagioclase

A type of feldspar with the formula (Ca,Na)AlSi3O8, the solid solution (Ca,Na) indicating a series of minerals, one end of the series with calcium CaAl2Si2O8, called anorthite, and the other end with sodium NaAlSi3O8, called albite

hanksite

Na22K(SO4)9(CO3)2Cl

Limestone

contain the remains of microscopic creatures and thus originate from biological processes

birefringence

meaning they polarize light into two wave components vibrating at right angles to each other

carbonic acid

The most abundant natural acid

evaporites

minerals formed by evaporation.

Hematite

a type of iron oxide that occurs in many different crystal forms

halides

consist of halogens ionically bonded with sodium or other cations

Sulfides

metals bonded to sulfurs. The largest sources of nickel

Sulfates

a combination of sulfur and oxygen (SO4–2)

Gypsum

is often formed from evaporating water and usually contains water molecules in its crystalline structure

Phosphate minerals

have a tetrahedral phosphate unit (PO4-3) combined with various anions and cations

Native element minerals

Usually metals, occur in nature in a pure or nearly pure state

Luster

describes hoe the mineral looks

Metallic

refers to a shiny appearance

Nonmetallic

May be described as vitreous (glassy)

Streak

seen when a mineral sample is scratched or scraped on an unglazed porcelain streak plate

Fredrick Mohs

development of the hardness scale

Crystal habit

how their crystals grow and appear in rocks

euhedral crystal

a habit which forms perfectly formed, unconstrained shape.

Twinning

a habit which occurs when the crystal structure replicates in mirror images along certain directions in the crystal

Striations

are optical lines on a cleavage surface

Cleavage planes

are smooth

Fracture

characteristic breaking patterns of minerals

specific gravity

a mineral property tied to gravity

heft

qualitative property a result of a high density

magnetism

attractive property to magnets

iridescence

property of scattering light

fluorescence

a property which gives some materials the ability to emit visible light when exposed to ultraviolet rays

phosphorescence

a property which allows minerals to absorb light and slowly release it