How to identify a mineral by its properties Mineral ID How to identify a mineral by its properties Baker 7th grade science

Rocks vs. Minerals…. What’s the difference Rocks vs. Minerals….. What’s the difference? All rocks are made of 2 or more minerals, but minerals are not made of rocks. A mineral is a solid material found in nature that is not made up of living things. Minerals have a specific crystal form properties There are about 2000 known minerals on earth. Mineral is like an element – pure Rock is like a compound- made up of 2 or more minerals

Today you will learn Which mineral properties are most important in identification. How mineral are identified by their properties. Baker 7th grade science

A mineral’s appearance helps identify it. In order to identify a mineral, you need to observe it properties – characteristics that help identify it. There are 4 main properties that we use to identify. Color, Luster, Streak and Hardness Baker 7th grade science

Mineral Property #1 Color Color is the first thing someone notices when they view a mineral. The color of a mineral is based on its chemical composition Color is one of the big reasons that attract people to minerals.

Generally speaking, color is not a good property to be used in the identification of minerals. It is usually the first property to confuse a novice collector into making an incorrect identification. Many minerals have different colors and some minerals' colors are identical to other minerals' colors. Baker 7th grade science

Mineral Property Streak Streak is closely related to color, but is a different property because the color of the mineral may be different than the color of the streak. Baker 7th grade science

Streak is actually the color of the powder of a mineral. It is called streak because the proper way to test for streak is to rub a mineral across a tile of white unglazed porcelain and to examine the color of the "streak" left behind. Baker 7th grade science

Streak Pyrite (known as "Fool's Gold") is always brassy yellow when found in crystals, even broken crystals, of any size; but when powdered, produces a black streak. Gold's streak, by the way, is yellow! Hematite's streak is blood- red Galena's streak is lead gray Baker 7th grade science

Mineral Property # 2 Luster A mineral’s luster is the way in which light reflects from the surface. The two major types of luster are metallic & nonmetallic. Baker 7th grade science

Some other ways to describe luster are Dull - just a non-reflective surface of any kind Earthy - the look of dirt or dried mud Fibrous - the look of fibers Greasy - the look of grease Metallic - the look of metals Pearly - the look of a pearl Silky - the look of silk, similar to fibrous but more compact Waxy - the look of wax

What is the first thing someone notices about a mineral? Quick Check What is the first thing someone notices about a mineral? What do we call the color of the powdered mineral? Baker 7th grade science

Hardness A mineral’s hardness is its resistance to being scratched. A scale known as the Moh’s scale is often use The classic scale for hardness was published in 1822 by Frederick Mohs, an Austrian mineralogist who got the basic concept from scratch tests performed routinely by miners. The scale selects 10 minerals as standards, arranging in order of increasing hardness. Baker 7th grade science

The classic scale for hardness was published in 1822 by Frederick Mohs, an Austrian mineralogist who got the basic concept from scratch tests performed routinely by miners. The scale selects 10 minerals as standards, arranging in order of increasing hardness.

Mohs Scale Baker 7th grade science

Brain Check 2 major types of Luster are…… Use the Mohs hardness Scale. Name three things you can scratch Calcite with. Baker 7th grade science