MineralsChris Medellin

Mineral Properties

Chris MedellinScience

6th Period Choate2/10/14

5 Properties of MineralsColorLusterStreak

Specific GravityHardness

Color The color of a specimen in the light.

Although most people think of color as an important characteristic of a specimen, it is not very useful in identifying a mineral.Quartz is a mineral that comes in many different colors, for example rock crystal (colorless), citrine (yellow), smoky quartz (brown), amethyst (violet), vermarine (green), aventurine quartz (blue).

Amethyst Purple

Rock Crystal White

Smokey Quartz Brown

Examples of Color

Luster What the surface looks like in the light.

dull very dull, mainly in minerals kaolinite, orthoclase

that are porous

pearly like a pearl, play of colors talc, muscovite mica

silky has a shiny surface gypsum, kernite, ulexite

like a piece of silk cloth

glassy looks like glass quartz, obsidian

metallic very shiny, pyrite, gold, silver

like processed metals,

The shine of a mineral in light can be used to identify a specimen, this is called luster and ranges from dull to glassy to metallic.

Dull Glassy Metallic

Examples of Luster

Streak The color of a mineral’s dust

The streak of a mineral is the color of the powder left on a streak plate (piece of unglazed porcelain) when the mineral is scraped across it.

The streak plate is essentially a type of glass, so it isn't used on minerals with hardness greater than 7.

Examples of Streak

Specific Gravity Indicates how many times more the mineral weighs compared to an equal amount of water.

very light < 2 borax

light 2 - 2.5 gypsum

average 2 – 3 quartz

above average 3 - 4 mica

Heavy 4 – 5 garnet

very heavy 5 – 10 hematite

extremely heavy > 10 gold, silver

super heavy 20+ platinum!

So if you have a bucket of silver, it would weigh 10 times as much as a bucket of water. If you have a bucket of quartz, it would only weigh about 2 1/2 times as much as a bucket of water.

Examples of Specific GravityTurquoise (2 times the weight of water)Mica (4 times the

weight of water)

Gold (10 times the weight of water)

Hardness The resistance of a mineral to scratching.

Scratching a mineral helps us identify a specimen. The hardness of a mineral was described by the Moh’s scale. This scale was created in 1812 by the geologist and mineralogist Friedrich Mohs.

Examples of HardnessTalc (very soft)

Topaz (very hard)

Diamond (the hardest)

Now that you know about The 5 Properties of a MineralCan you identify this Mineral?

Identifying a specimen using mineral properties.

Color

This specimen is colored metallic yellow

Specific gravity

One bucket of this specimen weighs 10 times as much as a bucket of water.

Streak

The streak of this specimen is gold yellow.

Luster

The luster of this specimen is metallic

Hardness

The hardness of this specimen is a 2.5 which means it can be easily scratched with a nail.

Conclusion

Based on the properties of this specimen I conclude, that this is gold.

About Gold Native gold is an element and a mineral. It is highly prized by people because of its attractive color, resistance to tarnish and its many special properties - some of which are unique to gold. Its rarity, usefulness and desirability make it command a high price.

ResourcesImages from Google SearchInformation on Quartz from www.mindat.orgInformation on Gold from www.geology.comInformation on Streak from www.minerals.netInformation on Mohs Hardness Scale from geology.about.comInformation on Minerals from daisyduckdiv1.weebly.com/rocks-

and-minerals.html