Minerals

Minerals

• Minerals are naturally occurring, solid, crystalline, inorganic substances with a definite chemical composition.

Minerals

• Minerals might be made of one element, such as:– Gold– Silver– Copper– Diamond

Minerals

• …but most minerals are made of more than one element combined together:– Ruby = Al2O3 + Cr

– Emerald = Be3Al2(SiO3)6

– Feldspar = KAlSi3O8 – NaAlSi3O8 – CaAl2Si2O8

– Sapphire = Al2O3 + V, Ti, or Fe (for purple, white, or yellow/green)

– Halite = NaCl

Minerals

• Most minerals end in the word “ite” to identify it as a mineral.– Malechite– Hematite– Magnetite– Pyrite– Halite– Graphite– Wolframite

Minerals

• There are about 3700 different types of minerals on the earth that we know of, and about 100 new minerals are discovered each year.

Minerals

• The most common minerals on earth are:– Quartz (most common

on Earth’s surface)– Feldspar (most common,

in crust, but is a combination of several different types of minerals.)

– Olivine (Most common in the mantle)

Minerals

• The most rare minerals in the Earth are:– PAINITE (18 exist)– SERENDIBITE– POUDRETTEITE– GRANDIDIERITE– JEREMEJEVITE– RED BERYL– TAAFFEITE– BENITOITE

Birthstones

• Most birth “stones” are actually minerals.

• Some months have a birthstone and a birth gemstone because not all minerals work well for jewelry

Mineral properties

• Minerals are identified by the properties that they have.

• Just like each element has it’s own set of properties that help identify it, each mineral has it’s own properties.

Minerals - properties• Luster tells how well a

mineral reflects light.• A minerals luster might

be:– Metallic (shiny like a metal)– Nonmetallic (not very

shiny)• Waxy• Vitreous (glassy)• Pearly• Oily• Adamantine (brilliant like

diamond)

Minerals - properties

• Hardness describes how hard it is to scratch the mineral.

• The Moh’s hardness scale is used to find the hardness of a mineral.

Minerals - properties

• Cleavage describes how the mineral breaks. (Does it break along certain planes?)

Minerals - properties

• Color is important in identifying most minerals.

Ruby Sapphire

Minerals - properties

• But color can be deceptive

Minerals - properties

• Streak is the color that the mineral is when it is a powder.

• A streak plate is used to find a minerals streak color.

Minerals - properties• Other properties that

might be used to identify minerals include:– Magnetism (tiny bits of

magnetite in migrating birds)

– Reaction with certain chemicals

– Smell– Taste– Flourescence– Crystal structure

Minerals Rocks

• Minerals combine to form rocks

• Mineral + mineral = rock

Rocks

• Rocks don’t have a definite chemical composition like minerals do because they’re made of lots of “pieces” of different minerals all hooked together.

Rocks

• There are 3 main types of rocks:– Sedimentary– Igneous– Metamorphic