Properties of Minerals Geologists use characteristics to tell one mineral from another Students need to be sitting in groups of 4 or 6 for the activities in this power point Lay out mineral samples as well as steak plates, pennies and nickels in the middle of the desks

Mineral Properties we will study Texture Cleavage Hardness Luster Streak Color

Other physical properties you know Shape Size Mass Weight Volume Density State of Matter

Minerals Song/Chant Minerals on Earth are always pure in form Recited as a chant or sung to the tune of “She’ll Be Comin’ Round the Mountain” Chorus Lyrics adapted from Jenni Dent (Project GLAD) Minerals on Earth are always pure in form They have crystals and are solid, That’s the norm! Color, luster, hardness, streak They are classifying techniques And are properties we use to inform. Students will either copy or attach this song in their Science notebook/journal and sing or chant it for the rest of the week

Texture How the surface of a mineral feels to the touch It can be rough or smooth An unpolished mineral normally has rough texture

Smooth

Rough Calcite: Gypsum:

Hardness Is measured by how easy it is to scratch. Geologists order the hardness by… Scratched by a fingernail. Scratched by a penny. Scratched by a nail. Scratched by a diamond.

The scale to measure the hardness of a mineral is the Mohs Scale: http://www.mineraltown.com/infocoleccionar/mohs_scale_of_hardness.htm

Gypsum is soft, it can be scratched by a fingernail.

Calcite is soft, but a little harder because it cannot be scratched by a fingernail, but it can be scratched by a penny.

Fluorite is harder. It can be scratched by a nail, but not a penny or fingernail.

Diamonds are the hardest mineral, so it scratches every mineral.

Streak The powder mineral leaves Red chalk on a chalk board makes red marks. White chalk makes white marks. Not all minerals work this way. When some minerals are scratched along a ceramic streak plate, it creates a different color.

Gold When gold is run across a streak plate it makes a yellowish-gold color. That makes sense.

Pyrite or “Fool’s Gold” When pyrite is run across a streak plate, it has a black or dark green streak. Pyrite is not worth much money, while gold is worth a lot. They look alike, so miners call it fool’s gold.

Hematite Hematite’s color is grey, but its streak is red. Hema means blood. The mineral was named hematite because it looked like it was bleeding when it was taken across a streak plate.

Cleavage How a mineral is split Not all minerals have cleavage. Some minerals split easily along a flat surface.

Mica has cleavage in one direction. It breaks along one line.

Feldspar has two lines of cleavage. It breaks along two lines.

Luster Refers to the way light reflects from the surface of the mineral. There are two types of luster, Metallic: looks like polished metal. Nonmetallic: does not look like polished metal. Nonmetallic can be shiny or dull.

Pyrite has metallic luster

Quartz has nonmetallic luster

One mineral property we know is… COLOR

A mineral can be many different colors. Below is Mica.

Many minerals can be the same color. Below are gold colored minerals Many minerals can be the same color. Below are gold colored minerals. Which one is gold?

None of them were real gold. The answer… None of them were real gold.

Just like with people… Outside color does not tell you much about the important characteristics.