Warm Up Describe what a mineral is.

inorganic Naturally occurring solid Crystal structure definite chemical make-up Video clip “What is a mineral?’

Minerals are 1.Naturally Occurring – to be a mineral, it must occur naturally 2.Inorganic – does not arise from materials that were once part of living things 3.Solid – a mineral is always solid with a definite volume and shape

Minerals are 4.Crystal structure – a pattern that repeats over and over with faces that meet at sharp edges and corners 5.Definite Chemical Composition – contains certain elements in definite proportions a.Element – a substance composed of a single kind of atom b.Compound – two or more elements chemically combined

gold water coal rubies petroleum diamonds Here is a hard one – What about ice?

Minerals are identified by their 1.Hardness – a mineral can scratch any mineral softer than itself but will be scratched by a mineral harder than itself a.Mohs Hardness Scale – ranks minerals from softest to hardest on a scale of one to ten. Talc is the softest known mineral, and diamond is the hardest known mineral.

Warm Up Is glass a mineral? Why or why not?

Minerals are identified by their 2.Color – some minerals are always the same color (malachite is always green and azurite is always blue); most minerals come in a variety of colors

Minerals are identified by their 3.Streak – the color of a mineral’s powder; the color of a mineral’s streak does not change like the color of the mineral may

Streak is the color of a mineral powder. Many minerals appear a different color when powdered than they do as a big piece. The color may be entirely different, or it may be a different shade.

Minerals are identified by their 4.Luster – how a mineral reflects light from its surface; some ways to describe luster are shiny, earthy, metallic, waxy, and pearly

Copyright © Dr. Richard Busch Courtesy United States Geological SurveyUnited States Geological Survey Courtesy United States Geological SurveyUnited States Geological Survey Each reflects light differently – that is luster! Which of these words would you use to describe these minerals? Glassy, metallic, dull, silky, waxy, pearly

Waxy luster Glassy luster dull luster metallic luster Glassy luster

Minerals are identified by their 5.Density – all minerals have a characteristic density; no matter the size of the sample, its density will remain the same

How tightly packed the atoms are will make something heavy. Every mineral has its own density. These two items may have the same size – but do not weigh the same. Why?? Because the brick has atoms that are more tightly packed together than the styrofoam.

This means for equal size, they have their own special weight. Which one is worth more? How could you tell? The first one is topaz (worth a lot) and the second is citrine quartz (not worth a lot). A scientist would measure their densities and they would be different!

Copyright © Dr. Richard Busch Crystal video clip

Minerals are identified by their 6.Crystal System – the crystal structures are divided into six groups a.Cubic b.Hexagonal c.Tetragonal d.Orthorhombic e.Monoclinic f.Triclinic

Cleavage means it breaks the same way every time. Fracture means it breaks in a random pattern that cannot be predicted. Calcite and halite break a special way. donsmaps.com Quartz and chert break in a random pattern. There is not way to predict how they break.

Minerals are identified by their 7.Cleavage and fracture – the way a mineral breaks apart helps us identify it a.Cleavage – splits apart along flat surface b.Fracture – breaks apart in an irregular way

Minerals are identified by their 8.Special Properties – some minerals are identified by their special properties a.Fluorescence – minerals that glow under ultraviolet light b.Magnetism c.Radioactive d.Chemically Reactive e.Electrical Properties

Special Properties Magnetism Radioactivity Chemical Reaction Fluorescence Salty Taste But NEVER taste things in the lab! Double Image

Can you name some we just discussed? Click here for a review of properties of minerals video clip