Chapter 2Chapter 2

Mineral Identification

Mineral Identification Tests

colorlusterstreakcleavage

Mineral Identification Tests

fracturehardnessspecific gravity or heftacid test

Colorminerals can be found in various levels of purity

so they may not always look the same.ex: cinnabar, an ore of Mercury is red malachite, an ore of Copper is greenWhat are the drawbacks of using color in

identification?

Color❶ Several minerals can have the same color❷ Impurities can change the color of a mineralex: iron causes quartz to turn from colorless to

purple. titanium causes quartz to turn pink

Color

❸ Air causes minerals to change color. silver turns black and copper changes to green

Luster - how it shines

● metallic - shines like a metal

● must be a metal

● non - metallic - different kinds of shine because it is not metallic

● vitreous - glass● adamantine - like a

diamond● pearly - soapy - waxy

Streak - true colordone by marking mineral on porcelain platemark left is true color of mineralsome minerals will have a white streak , while

other will have no streak

Cleavage - breakage planes

minerals that tend to break apart easily along a flat surface

mica - thin flat sheetsgraphite - flat surfaces in hexagonshalite - cubes

Fracture

minerals that break irregularlyconchoidal - inside of a shell - obsidianfibrous - jagged edges - coppersplintery

Scales of Hardness

● Mohs scale ● 1-10● 1 - talc very soft● 10 - diamond

● Field scale - 1-10 ● finger nail = 2 or less● copper penny = 3● steel knife = 4 or 5● scratch glass = 6 to 7

Specific Gravity or Hefta comparison of a mineral that is weighted both

in water and in the airthis is a ratioit gives an idea of the number of atoms or

molecules in a given space or size

Acid test

Some minerals will fizzzzzzz when HCl is placed on it.

calcite - limestone - marble willthey are made of Ca CO3.

the fizz is CO2 gas being released

Special Properties

Florescence - some minerals will glow when placed under ultra - violet light

taste - halite tastes saltyradioactivity - some minerals give off energy of

their owndouble refraction - seeing double - calcite