…the same type of mineral! They are examples of quartz!!

There are over 3000 types of minerals in the Earth’s crust

As you could see with the quartz, often times even the same kind of minerals can look very different

Therefore, geologists (scientists who study minerals and rocks) often use several different tests to determine type of a mineral they have found!

Color is obviously one of the most noticeable characteristics of a mineral, but it also the least reliable of all the characteristics

The color of a mineral is often caused by tiny amounts of other elements or compounds inside

For example, what people call amethyst is actually just quartz with iron in it!

The way that a mineral reflects light from its surface is its luster

The two types of luster are:- metallic- nonmetallic

Metallic Luster

Texture describes how a mineral feels to the touch.

Minerals can range anywhere between glassy feeling, rough feeling, greasy feeling, and even soapy feeling!

Talc has a soapy texture.

Fluorite has a glassy texture.

When a mineral is rubbed against a tile, it will leave behind a colored powdered streak on the tile

Sometimes a mineral’s streak does not match the mineral’s external color

For example, one way to tell the difference between pyrite (Fool’s gold) and real gold is by streak. Pyrite leaves a greenish-black streak while real gold leaves a yellow streak.

Hardness is a measure of how easily a mineral can be scratched

Geologists use Mohs scale to give minerals their hardness ratings

Hardness Mineral Associations and Uses

1 Talc Talcum powder.

2 Gypsum Plaster of paris. Gypsum is formed when seawater evaporates from the Earth’s surface.

3 Calcite Limestone and most shells contain calcite.

4 Fluorite Fluorine in fluorite prevents tooth decay.

5 Apatite When you are hungry you have a big "appetite".

6 Orthoclase Orthoclase is a feldspar, and in German, "feld" means "field".

7 Quartz  

8 Topaz The November birthstone. Emerald and aquamarine are varieties of beryl with a hardness of 8.

9 Corundum Sapphire and ruby are varieties of corundum. Twice as hard as topaz.

10 Diamond Used in jewelry and cutting tools. Four times as hard as corundum.

The pattern of atoms will determine how a mineral will break

A mineral that breaks relatively easily and evenly at angles is said to have cleavage

Minerals that break with rough or jagged edges are said to have fracture

Some minerals have unique propertiesFor example, Iceland spar can create double

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Calcite reacts with hydrochloric acid and releases carbon dioxide (bubbles)