The Earth’s Crust Mineral Identification

Mineral Identification What differences can you see between these minerals that could help identify them? What properties could be used to identify minerals?

What differences can you see between these minerals that could help identify them?

What properties could be used to identify minerals?

There are six main characteristics that we will use to identify minerals: 1. colour 2. crystals (the shape of) 3. hardness 4. streak 5. cleavage and fracture 6. luster Cadburys chocolate hardly stays creamy for long

There are six main characteristics that we will use to identify minerals:

1. colour

2. crystals (the shape of)

3. hardness

4. streak

5. cleavage and fracture

6. luster

Cadburys chocolate hardly stays creamy for long

1. Colour Colour - It's pretty easy to tell the colour of a mineral and it can give a clue to the identity of the mineral. However, colour alone cannot identify a mineral. For example, pyrite (fools gold) and gold are both the same colour.

Colour - It's pretty easy to tell the colour of a mineral and it can give a clue to the identity of the mineral.

However, colour alone cannot identify a mineral. For example, pyrite (fools gold) and gold are both the same colour.

In addition, a mineral can come in more than one colour. For example, the mineral corundum can occur in several different colours due to impurities. Corundum is better known as amethyst (purple), emerald (green), topaz (yellow), and ruby (red). In its pure form, corundum is white.

In addition, a mineral can come in more than one colour.

For example, the mineral corundum can occur in several different colours due to impurities.

Corundum is better known as amethyst (purple), emerald (green), topaz (yellow), and ruby (red).

In its pure form, corundum is white.

2. Crystals Crystal shape – Minerals sometimes occur as crystals. A crystal occurs naturally and has straight edges, flat sides, and regular angles. Each mineral forms a specific shape of crystal so it can be used for identification purposes.

Crystal shape – Minerals sometimes occur as crystals. A crystal occurs naturally and has straight edges, flat sides, and regular angles.

Each mineral forms a specific shape of crystal so it can be used for identification purposes.

3. Hardness Hardness – the hardness of a mineral can be measured and compared to other minerals using the Moh’s Hardness Scale . The scale goes from one (the softest) to 10 (the hardest) and ranks minerals on their “scratchability” 10 (hardest) diamond Emery paper (9.0) 9 corundum Sandpaper (7.5) 8 topaz Streak plate (7) 7 quartz Steel file (6.5) 6 feldspar Glass (5.5) 5 apatite Iron nail (4.5) 4 fluorite Copper penny (3.5) 3 calcite Fingernail (2.5) 2 gypsum Soft pencil point (1.5) 1 (softest) talc Hardness of Common Items Mineral Hardness Mineral

Hardness – the hardness of a mineral can be measured and compared to other minerals using the Moh’s Hardness Scale .

The scale goes from one (the softest) to 10 (the hardest) and ranks minerals on their “scratchability”

4. Streak Streak – the colour a mineral leaves behind when it is rubbed on a hard surface (usually a streak plate) Often the colour a mineral leaves behind is different from the colour of the mineral.

Streak – the colour a mineral leaves behind when it is rubbed on a hard surface (usually a streak plate)

Often the colour a mineral leaves behind is different from the colour of the mineral.

5. Cleavage and Fracture Cleavage and Fracture – Describes how a mineral breaks apart

Cleavage and Fracture – Describes how a mineral breaks apart

The way a mineral breaks apart can be a clue to its identity. If it breaks along smooth, flat surfaces, or planes, it is said to have cleavage . e.g. calcite or mica - Mica can be pulled apart into thin, flat, sheets and Halite forms flat edges when broken.

The way a mineral breaks apart can be a clue to its identity.

If it breaks along smooth, flat surfaces, or planes, it is said to have cleavage .

e.g. calcite or mica - Mica can be pulled apart into thin, flat, sheets and Halite forms flat edges when broken.

If it breaks with rough or jagged edges, it is said to have fracture. E.g. obsidian Obsidian fractures when broken apart leaving rough, jagged edges.

If it breaks with rough or jagged edges, it is said to have fracture. E.g. obsidian

Obsidian fractures when broken apart leaving rough, jagged edges.

6. Lustre Lustre – the way a mineral reflects light The "shininess," or lustre of a mineral depends on how light is reflected from its surface.

Lustre – the way a mineral reflects light

The "shininess," or lustre of a mineral depends on how light is reflected from its surface.

The surface of a mineral can reflect light in many different ways including: 1. Metallic Lustre - the mineral reflects light like a polished piece of metal.

The surface of a mineral can reflect light in many different ways including:

1. Metallic Lustre - the mineral reflects light like a polished piece of metal.

2. Vitreous Lustre (Glassy) - the mineral reflects light like a piece of glass when it is tilted from side to side.

2. Vitreous Lustre (Glassy) - the mineral reflects light like a piece of glass when it is tilted from side to side.

3. Pearly Lustre - the mineral reflects light like a pearl.

3. Pearly Lustre - the mineral reflects light like a pearl.

4. Dull Lustre - the mineral scatters the light and will not appear shiny at all.

4. Dull Lustre - the mineral scatters the light and will not appear shiny at all.