Warm Up

Minerals that are silicates contain ___________ and ____________.

**Turn in your mineral vocabulary to the HW box!!***

Identifying Minerals

Ways to identify a mineral

• Color

• Luster

• Streak

• Cleavage and Fracture

• Hardness

• Density

• Special properties

Color

• NOT a good way to identify a mineral.

• Two different minerals can be the same color.

• The same mineral can be different colors

fluorite amethyst

Luster

• The way the mineral reflects light.

• Metallic – looks like metal

• Submetallic – dull, but reflective

• Nonmetallic – dull or clear

Streak

• The color of a mineral’s

powder

• Found by rubbing the mineral across a streak plate (ceramic tile)

**The streak color may not match the mineral’s color!**

Cleavage and Fracture

• Cleavage – breaks along smooth edges (layers)

• Fracture – breaks along uneven or irregular surfaces (jagged edges)

Mica – example of cleavage

Quartz – example of fracture

Hardness

• A mineral’s resistance to being scratched.

• Ranked from 1-10 on Moh’s Hardness Scale. 1=softest, 10=hardest

Density

• The amount of matter in a given space

• When compared to water, it is called specific gravity.

Special Properties

• Fluorescence – glows under UV light

• Magnetism – natural magnet

• Chemical reaction – bubbles or fizzes w/acid solution

• Taste – halite tastes salty

Normal light UV light

Calcite fizzing from acid